PHYSICS I Salmon Test Corrections - NJ Science League · 2020-02-02 · s at an angle of 60o above...

PHYSICS I Salmon Test Corrections: JANUARY 10, 2019

Directions: For each question or statement fill in the appropriate space on the answer sheet. Use the letter preceding the word, phrase, or quantity which best completes or answers the question. Each of the 25 questions is worth 4 points. Use: g = 210m

s− and the vertically upward direction is positive unless specifically stated otherwise.

Ignore air resistance unless specifically stated otherwise. 1. The diagram below represents the US Government’s attempt to convert from the English/Imperial to the metric system (SI) in the 1970’s. This particular sign was posted for a brief time on a Florida road. Which statement provided is most accurate? (A) Florida decided to begin the conversions in areas where the posted speed limit was 30MPH since it is easily converted to another nice easily understood “round” number: 40km

h .

(B) This sign is axiomatically incorrect;30MPH is much slower than 40kmh .

(C) This sign is axiomatically incorrect;30MPH is much faster than 40kmh .

(D) Officials decided it was just too much information on one sign for drivers to understand. Use the following information for Questions #2 - #4: Below is a velocity/time graph of a single object in motion in a straight line. The object starts at rest at 0t = .

2. What is the physical meaning of the slope of the line in the above graph? (A) The displacement of the object from 0 to ft t t= = (B) The average speed of the object from 0 to ft t t= =

(C) The instantaneous speed of the object from 0 to ft t t= = (D) The acceleration of the object from 0 to ft t t= =

3. What is the physical meaning of the area above the line bounded by the x-axis in the above graph, shaded triangle shown to the right for clarity?

(A) The displacement of the object from 0 to ft t t= = (B) The average speed of the object from 0 to ft t t= =

(C) The instantaneous speed of the object from 0 to ft t t= = (D) The acceleration of the object from 0 to ft t t= = 4. For you math aficionados, this v/t graph occupied only the 4th Quadrant of a full xy-coordinate plane. This indicates that (A) the speed of this object is decreasing. (B) the acceleration of this object is decreasing. (C) the speed of the object is increasing. (D) the acceleration of the object is increasing.

NJSL Phy I Jan 2019 Exam

Use the following information for Questions #5 - #7: Just this past October 11, 2018, a Russian Soyuz rocket carrying NASA astronaut Nick Hague and Russian cosmonaut Alexey Ovchinin to the International Space Station failed during its ascent, sending the crew capsule falling back toward Earth in a dangerous ballistic (freefall) re-entry. The capsule with crew hard-landed safely to the ground after emergency parachutes deployed. According to NASA, the 2nd stage of the rocket failed 119 seconds after launch and the crew capsule separated and fell back to Earth.

To make the calculations manageable without the use of advanced Calculus and differential equations for the following three questions, an idealistic situation of the Soyuz near-disaster is presented with several non-real assumptions. Assume the Soyuz rocket accelerates from rest at a constant rate of 210 m

s at an angle of 60o above horizontal, continues

accelerating in a straight line path, the crew capsule separates immediately when the 2nd stage fails 119 seconds after lift-off, 210mg s= − along the entire rocket/capsule path, air resistance is negligible, and this all takes place above level

horizontal ground. 5. Assuming the straight path acceleration as mentioned above, what is the vertical height of the Soyuz rocket above the ground at the instant of rocket failure? (A) 53.1km (B) 61.3km (C) 70.8km (D) 114.4km 6. Upon separation from the rocket, to what maximum height above the ground does the crew capsule reach before beginning the long fall back to Earth? (A) 53.1km (B) 61.3km (C) 70.8km (D) 114.4km 7. Assuming basic ideal projectile motion of the crew capsule after separation (ignoring air resistance and parachute drag), how far horizontally from the launch site does the crew capsule land? (A) 35.4km (B) 114.4km (C)151.3km (D) 186.7km 8. A Fizzix text book is thrown horizontally from a window 30m above the level ground by a frustrated high school student. The trajectory of the book causes it to strike the ground at an angle of 45o to the horizontal. What is the speed at which the book hits the ground? (A) 24.5m

s (B) 34.6ms (C) 45m

s (D) 54.4ms


https://www.space.com/16748-international-space-station.html

9. A circus performer of mass M is temporarily suspended motionless from two ropes as shown below. T1 and T2 represent the tensions in the ropes. θ1 and θ2, where 2 1θ θ> , represent the angles of the ropes as measured from the vertical. Which entry in the chart provided represents the tensions in the ropes?

1T 2T

(A) 1 21

2

sin coscossin

Mgθ θθ

θ+

2 1

21

sin cos cossin

Mgθ θ θ

θ+

(B) 1 21

2

sin coscossin

Mgθ θθ

θ−

2 1

21

sin coscossin

Mgθ θθ

θ+

(C) 1 21

2

sin cos cossin

Mgθ θ θ

θ+

1 2

12

cos sin sincos

Mgθ θ θ

θ+

(D) 1 21

2

sin cos cossin

Mgθ θ θ

θ−

1 2

12

cos sin sincos

Mgθ θ θ

θ−

Use the following information for Questions #10 & #11: The diagram below depicts a construction worker trying to hoist a heavy container up a ramp onto a level platform. The container has a mass M and experiences a frictional force of µk while sliding against the ramp. The ramp makes an angle of θ with the horizontal and is of a length L. The worker pulls on a rope that is in contact with two frictionless massless pulleys. The worker pulls with a force F which then causes a tension T in the rope attached to the container.

10. Assuming the applied tension T is less than the weight of the worker (otherwise, he would just do a rope climb…), with what acceleration does the container slide up the length of the ramp?

(A) sin coskT g gM

θ µ θ− − (B) sin coskT g gM

θ µ θ+ +

(C) cos sinkT g gM

θ µ θ− − (D) cos sinkTg gM

θ µ θ+ −


11. Upon reaching the top of the ramp, the container gets snagged on something and stops. The worker pulls as hard as he can only to see the rope snap and the container slide back down the ramp. With what speed does the container reach the bottom of the ramp? (A) ( )2 sin coskgL θ µ θ− (B) ( )2 cos sinkgL θ µ θ−

(C) ( )sin coskgL θ µ θ− (D) ( )cos sinkgL θ µ θ− Use the following information for Questions #12 & #13: An object of mass M is moving in a circle of radius R at a constant speed V while experiencing a net force of F. 12. If the radius is doubled to 2R while keeping the speed of the object the same at V, what is the new net force acting? (A) 4

F (B) 2F (C) 2F (D) 4F

13. If each quantity is doubled to 2M, 2R, and 2V, what is the new net force acting? (A) 4

F (B) 2F (C) 2F (D) 4F

14. As shown below, a 1000kg sports car attempts to navigate a circular unbanked racetrack turn of radius 50R m= at a

speed of 30mV s= . The coefficient of static friction between the tires and racetrack surface is 0.8sµ = .

The sports car will (A) successfully make the turn. (B) slide into the inside of the turn (left of the direction of travel through the turn). (C) slide off into the outside of the turn (right of the direction of travel through the turn). (D) successfully make the turn ONLY IF it accelerates into the turn with 22ma s≥ .

15. A satellite is in elliptical orbit around the Earth. Consider the following three vector quantities associated with the satellite:

I. FΣ , the net force acting on the satellite at any instant. II. v , the instantaneous velocity of the satellite at any instant. III. a , the net acceleration of the satellite at any instant.

Which of the following statements is a correct relationship between I, II, & III at any given instant? All full credit. Should have said satellite in circular orbit. Key has D. (A) I, II, & III are all in the same direction at the same instant. (B) I & II are in the same direction at the same instant. (C) I & III are perpendicular to each other at the same instant. (D) II & III are perpendicular to each other at the same instant.


16. The gravitational constant in Newton’s Law of Universal Gravitation can be reduced to which of the following?

(A) 2

2m

kg s⋅ (B)

3

3m

kg s⋅ (C)

3

2m

kg s⋅ (D)

2

2 2m

kg s⋅

17. Earth has a mass of M and a radius of R . Let g denote the acceleration of gravity near the surface of Earth and G

denote the Universal Gravitational Constant. What is the ratio of G g ?

(A) 2R

M (B) RM (C)

2MR (D) 2

MR

18. According to Wookieepedia™ (The Star Wars Wiki), Tatooine, home planet of Luke Skywalker from the Star Wars™ franchise fame, has a diameter of 10,500km , making it just a little smaller than Earth (12,700km ). Assuming Tatooine

has a similar average density as Earth at 35,500kgm , what is the acceleration due to gravity on the surface of Tatooine?

(A) 26 ms (B) 28m

s (C) 210 ms (D) 216m

s

19. Not all writers get their science facts right, or even try hard. Another famous science fiction “planet” is LV-426 of the Aliens™ franchise. LV-426, 39 light years from Earth, is actually one of three moons orbiting a large gas giant planet that looks conspicuously like Saturn. According to the first Alien movie, LV-426 has a diameter of 1, 200km , one-third the size of our own Moon, which fits its on-screen description by Lieutenant Ellen Ripley (played by Sigourney Weaver), as a planetoid. It has a surface gravity of about 90% that of the surface of Earth. What must be the density of LV-426 in terms of Earth density, D, mentioned in #18 above? NOTE: In a later movie, Alien Resurrection, LV-426 was said to be 12,000km wide, destroying the “planetoid” description used in previous movies since this is almost the size of Earth. (A) 3

D (B) D (C) 3D (D) 9.8D

20. As diagrammed below, a force F inclined upward to the left at an angle of θ to the horizontal acts directly on mass M. Mass M is attached by a strong un-stretchable rope to another mass 3M. Both masses started at rest on a frictionless table and now have an acceleration, a, to the left. What is the relationship between the tension in the rope between the masses, T, and the applied force, F?

(A) cosT F θ= (B) 3 cos

4FT θ

= (C) 34

T F= (D) 3 cosT F θ=


Use the following information for Questions #21 & #22: Racecar speedways bank the curves to allow drivers to continue going at high speeds without too much worry of losing traction. The steepest banked curves are turns #1 & #2 at Talladega Superspeedway in Alabama at an incredible33o . Each of these turns is circular with a radius of

( )335 1100m ft . 21. What is the highest speed a 1500kg racecar can successfully navigate one of these Talladega curves if friction is negligible? (A) 25m

s (B) 47 ms (C) 72 m

s (D) 96 ms

22. What is the highest speed a 1500kg racecar can successfully navigate one of these Talladega curves if the coefficient of static friction between the tires and road surface is 0.75µ = ?

(A) 25ms (B) 47 m

s (C) 72 ms (D) 96 m

s

23. According to NASA, space debris left over from dead or wrecked satellites, used parts, booster parts, and tools dropped by clumsy astronauts is becoming increasingly dangerous. As of July 2018, the US Strategic Command is tracking a total of 17,852 artificial objects in orbit about Earth and only 1,419 of these are operational satellites. These 17,852 objects are only the ones large enough to be tracked from the ground; larger than 10cm . There is thought to be over 171 MILLION objects in total. To demonstrate the danger to astronauts and satellites alike, calculate the speed of a small 1kg hunk of debris that orbits Earth at an altitude of 1,000km . The mass and radius of Earth is 246 10x kg and

66.4 10x m , respectively. (A) 7,000m

s (B) 7, 400 ms (C) 7,900m

s (D) 8,500ms

Use the following information for Questions #24 & #25: The annual Iditarod Sled-Dog Race in Alaska takes teams of sled dogs and one human “musher” (driver) on a grueling 1,000 mile race from Anchorage to Nome. The start of the race requires a minimum of 12 dogs and a maximum of 16. The dogs have an average mass of 20kg and the sled/musher (driver) combination has a mass of 220kg . Each dog can exert a backwards force on the snowy surface of 175N . The static and kinetic coefficients of friction are 0.15 and 0.10, respectively. Assume the dog’s paws do not slip at any time. 24. What is the magnitude of the acceleration from rest during an initial “mush” (pull) using the maximum number of 16 dogs? (A) 23.7 m

s (B) 24.2ms (C) 24.6m

s (D) 24.8ms

25. What is the magnitude of acceleration once the sled starts to move assuming the dogs continue to exert the same force using the maximum number of 16 dogs? (A) 23.7 m

s (B) 24.2ms (C) 24.6m

s (D) 24.8ms


PHYSICS I Salmon Test JANUARY 10, 2019

SOLUTIONS Corrections: 1. C 14. C 2. D 15. D All full credit 3. A 16. C 4. C 17. A 5. B 18. B 6. D 19. D 7. D 20. B 8. B 21. B 9. A 22. D 10. A 23. B 11. A 24. C 12. B 25. D 13. D

Physics I Topics Salmon Test January Exam: Kinematic, Dynamics, Circular Motion, Universal Gravitation. February Exam: impulse and linear momentum and conservation of linear momentum: collisions, Work and Energy, Conservation of Energy, Plus review of Jan topics March Exam: Rotational kinematics, torque, rotational dynamics Conservation of angular momentum, Simple Harmonic motion: simple pendulum, Mass-spring systems Plus review of Jan and Feb topics April Exam: Introductory electrostatics: Concepts of electric charge Conservation of electric charge, Coulomb’s Law, DC circuits (resistors only) Mechanical waves and sound, Plus review of Jan, Feb, and March topics.

New Jersey Science League PO Box 65 Stewartsville, NJ 08886-0065

Phone (cell) # 908-213-8923 email: [email protected] Web address: http://entnet.com/~personal/njscil/html/

What is to be mailed back to our office? PLEASE RETURN THE AREA RECORD AND ALL TEAM MEMBER SCANTRONS

(ALL STUDENTS PLACING 1ST, 2ND, 3RD, AND 4TH). If you return Scantrons of alternates, then label them as ALTERNATES.

PHYSICS I Salmon Test FEBRUARY 14, 2019 Corrections:

Directions: For each question or statement fill in the appropriate space on the answer sheet. Use the letter preceding the word, phrase, or quantity which best completes or answers the question. Each of the 25 questions is worth 4 points.

Use: 210 mg s= − , the vertically upward direction is positive, and ignore air resistance unless specifically stated otherwise.

1. The diagram below, used in the January 2019 Exam, depicts a construction worker, John, trying to hoist a heavy container up a ramp onto a level platform. The container has a mass M and experiences a coefficient of friction of µk while sliding against the ramp. The ramp makes an angle of θ with the horizontal and is of a length L. The worker pulls on a rope that is in contact with two frictionless massless pulleys. The worker pulls with a force F which then causes a tension T in the rope attached to the container. How much work is done by the worker in raising the container at a constant speed through distance L?

(A) ( )sin cosKMgL θ µ θ+ (B) ( )cos sinKMgL θ µ θ+ (C) sin cosK

MgLθ µ θ+

(D) cos sinK

MgLθ µ θ+

2. Sammy Small lifts a 45-kg barbell during a workout in the weight room. Sammy moves the barbell upward through a distance of 80-cm in a time of 3-seconds. Arnold Strongman walks in and accomplishes the exact same action with the

same barbell in only one second. What is the ratio of the amount of work Arnold did compared to Sammy, Arnold

Sammy

WW

?

(A) 31

(B) 91

(C) 11

(D) 13

3. You attach a hefty 2-kg iron ball to a strong string of negligible mass and length 1-m creating a pendulum. You allow the mass to hang motionless for a few moments. From the equilibrium position, A, you raise the ball to an angle of 30o to the vertical and release it from rest. What is the tension in the rope as the ball passes through point A? (A) 14.6N (B) 20N (C) 23.3N (D) 25.4N 4. A heavy box of unused Fizzix Textbooks is slid across a rough horizontal surface by an applied force F oriented at an angle of θ to the horizontal. Using the data provided below, how much work is done by the force F in moving the box from point A to point B? The magnitude of 10 & 30oF N θ= = . The mass of the box is 12M kg= and there is a constant force of sliding friction 2fF N= . The distance between points A and B is 2X m= , and the

kinetic energy of the box at points A and B are 4 & 9A BKE J KE J= = , respectively. (A) 4J (B) 5J (C) 9J (D) 20J

NJSL Phy I Feb Exam 2019 Page 1

5. A 625 gram− basketball is bounced vertically on the floor. Just before striking the floor it has a speed of 4ms

downward and immediately after it bounced it has a speed of 3ms upward. If the ball is in contact with the immovable

floor for 0.15sec , what is the average force the floor exerts on the ball during the bounce? (A) Zero (B) 0.7N (C) 4N (D) 29N Use the following information for Questions #6 & #7: Another box of Fizzix textbooks of mass M is now dropped vertically downward from rest at a distance h above a vertically oriented ideal spring of spring constant k. Attached to the top of the ideal spring is a thin massless platform.

6. Using the provided variables and common physical constants, at what position relative to Xo does the mass reach a maximum vertical velocity? All full credit off topic

(A) At oX (B) Mgk

below oX

(C) 2Mg

kbelow oX (D)

2Mgk

below oX

7. If the following data is provided, at what position below Xo does the box stop?

4 , 2 , & 500 .NM kg h m k m= = = All full credit off topic

(A) 0.08m (B) 0.16m (C) 0.40m (D) 0.65m 8. The two diagrams below represent an overhead view of a racetrack turn at two different times for the same two identical cars. Figure #1 shows two cars already into the turn both traveling at the same speed, 1V . Car #2 is ahead of Car #1. Figure #2 shows the same racetrack with the same two cars just a few seconds after Figure #1. Car #2 has lost

control and spun around and is now traveling “backwards” at a speed of 13

V toward the front of Car #1. Assuming the

cars crash into each other head-on with the velocity vectors exactly opposite each other and stick together, what is the final speed of the Car #1 & Car #2 combination? NOTE: No professional car drivers were hurt in the production of this problem.

(A) 13

V (B) 123

V (C) 1V

(D) Impossible to tell without knowing the masses of the cars.


9. Taking problem #8 up a notch, two alien spy space cruisers in the same circular orbit traveling around the Earth are destined to slam into each other. Both alien cruisers are traveling at an altitude of one Earth radius. The radius and mass of Earth is 66.4 10x m and 246 10x kg , respectively . Cruiser #1 has a mass of 97.5 10x kg Cruiser #2 has a mass of

89 10x kg , but Cruiser #2 was inserted into orbit backwards by an alien engineer distracted by silly cat videos on our InterWebs and is traveling directly toward Cruiser #1. They collide in a perfectly inelastic fashion resulting in a mangled mess. At what altitude above Earth surface should the combined cruiser wreckage move to in order to obtain a stable circular orbit? (A) 66.4 10x m (B) 71.3 10x m (C) 71.4 10x m (D) 72.1 10x m 10. Our trusty construction worker from Question #1, John, is getting assistance from a not-so-trustworthy co-worker, Bobo, in lifting a heavy box of construction material up to a roof 20-m high. Both John and Bobo have a mass of 100-kg each and the box has a mass of 150-kg. Between the two, they manage to hoist the box all the way up to the pulley, 20-m above the ground. However, before John can securely tie-off the rope, Bobo thinks the job is done and lets go of the rope! John gamely holds onto the rope as the heavy box plummets to Earth and John gets pulled up to the pulley where he slams into it while Bobo runs away. How long does it take John to travel from the ground up to the pulley? (A) 2.0 seconds (B) 2.8 seconds (C) 4.5 seconds (D) 14.14 seconds 11. A typical car in the United States uses a gasoline engine that is 30% efficient. One gallon of gasoline contains

81.2 10x J of available chemical energy. One kilogram of Uranium 23592U used in a typical nuclear fission plant contains

138 10x J of available energy and the power plant itself operates at an efficiency of 40%. How many gallons of gasoline would you have to buy and consume in order for your car to have the same useful output as one kilogram of 235

92U ?

(A) 52.7 10x gal (B) 56.7 10x gal (C) 59.0 10x gal (D) 62.0 10x gal 12. Boxing gloves are heavily padded to decrease the force of the blow to the head. This is accomplished by: (A) Decreasing the change in momentum of the puncher’s fist. (B) Decreasing the change in momentum of the victim’s head. (C) Increasing the change in acceleration of the puncher’s fist. (D) Increasing the time of the blow to the head.


13. During a heated prolonged battle with a bad guy, Spiderman™ runs out of his potent spider webbing weapon and resorts to shooting Nerf® darts. As pictured below, he aims horizontally and fires a spring-loaded dart gun. This is done by pushing the dart of mass M into the barrel, thus engaging and compressing the ideal spring of spring constant k a distance X. The dart then leaves the barrel with a speed of V1 and travels a horizontal distance DH where it lands harmlessly on the ground in front of the bad guy. Spiderman then reloads an identical dart, but pushes it into the barrel twice as far, compressing the spring a distance of 2X. In terms of the quantities given and universally accepted physical constants, what is the horizontal distance of the 2nd shot assuming Spiderman still aims horizontally from the same height, h, and the bad guy can dodge the dart? All full credit Off topic.

(A) 2hkx

Mg (B)

22hkxMg

(C) 2

2 hkxMg

(D) 222 hkx

Mg

14. Your Fizzix teacher, Dr. Fizzix (Doc, for short), is a daredevil to be sure. While walking to school one morning, the 60-kg Doc sees a large 300-kg stationary wrecking ball hanging, Position A, from a crane platform 10-m above. Doc immediately recognizes a classroom demo just waiting to happen. Doc starts his GoPro™ camera and runs at a top speed

of 9ms toward the wrecking ball. At the last instant, Doc leaps onto the ball without losing any horizontal speed and

hangs on tightly as the ball swings upward till reaching Position B where the ball (and Doc) stop. What is the vertical position difference, H, between Position A and Position B? (A) 0.11m (B) 0.16m (C) 2.2m (D) 4.0m

15. The average solar power per square meter reaching the Earth surface is 21.1kWm after being partially absorbed and

partially reflected by our atmosphere. If the United States decided to convert all power production to solar, calculate the area required for solar panels to meet the needs of the entire country, 201.3 10 Jx yr . The total area of the United States

is 6 29.8 10x km and NJ is 4 22.25 10x km . Modern solar panels operate on a net efficiency of about 15% in NJ due to the curvature of the Earth and the limited sun exposure. (A) 2 22.5 10x km (B) 4 22.5 10x km (C) 6 22.5 10x km (D) 11 27.9 10x km 16. What is the efficiency of an out-of-shape Fizzix teacher who does 200,000 Joules of useful work running from the parking lot to class because he’s late? In so doing, the teacher metabolizes 900 kcal of food energy. NOTE: One kcal (kilocalorie) is the equivalent of 4200 Joules. (A) 0.05 (B) 0.10 (C) 0.15 (D) 0.20


17. A 100-kg basketball player is crouching down waiting for the ball to be tossed into the air by the referee. His center of mass has lowered a distance of 0.5m from his typical standing upright position. During his subsequent jump into the air, his feet leave the ground and his center of gravity rises 1.1m above his typical standing upright position. What was his power output during the jump phase from his initial crouch until his feet left the ground? Assume the force he exerts on the floor is uniform throughout the jumping phase. (A) 33.2 10x W (B) 39 10x W (C) 29 10x W (D) 23.2 10x W 18. Knowing that the mass of the Earth is 246 10x kg and its orbital radius about the Sun is an average of 111.5 10x m , calculate its linear momentum at any instant. Treat the orbit as circular.

(A) 289 10 kg mx s⋅ (B) 291.8 10 kg mx s

⋅ (C) 359 10 kg mx s⋅ (D) 365.7 10 kg mx s

⋅

Use the following information for Questions #19 & #20: A large bullet of mass M is fired horizontally with speed VB into a large wooden block of mass 50 M. The wooden block is sitting initially at rest on the right edge of a frictionless table that has a top at a height of H above the floor. 19. If the bullet is embedded within the wooden block and does not pass all the way through it, what is the horizontal distance dx the block-bullet combination hits the floor? All full credit.

(A) 250

BV Hg

(B) 251

BV Hg

(C) 2B

HVg

(D) 251 BHVg

20. If the bullet passes through the wooden block and exits the right side of the block at a speed of 2BV , what is the

horizontal distance dx the block-bullet combination hits the floor? All full credit. Key has D

(A) 250

BV Hg

(B) 251 BHVg

(C) 251

BV Hg

(D) 2100

BV Hg

21. A 95-kg ice hockey player hits a 170-gram puck, giving the puck a velocity of 50 m

s . If both the player and the

puck were at rest initially and the ice surface is perfectly frictionless, how far does the player recoil by the time the puck reaches the goal 20-m away? (A) 0.036m (B) 0.36m (C) 3.6m (D) 36m


22. Recently, NASA’s Dawn mission visited the large asteroid Vesta and the dwarf planet Ceres, the largest object in the asteroid belt. Dawn is the second space probe to use an ion propulsion engine that employs atomic ionization to produce much higher exhaust

velocities than conventional chemical thrusters. Dawn has a mass of 750-kg and expels ion exhaust at a speed of 68 10 mx s . Dawn’s

ion drive can achieve a neck-snapping 0-60 MPH in four days! (The 2019 Chevy Camaro SS can do that in four seconds!) This is achieved by an extremely small average thrust force measured in mN (milli-Newtons); just a small fraction of an ounce of force. The extremely small mass of the ion fuel, in this case Xenon, allows for long-term space travel without the fear of running out and you are not in a hurry.

Calculate the time required for Dawn to increase its speed by 40,000 kmhr if it expels 74 10 kgx s

− of ion exhaust at the

aforementioned velocity and maximum thrust force, which is unknown? Ignore any relativistic effects of the velocity of the fuel and that Dawn is already far away from any direct gravitational influences. (A) 3.75sec (B) 33.75 10 secx (C) 42.6 10 secx (D) 62.6 10 secx Use the following information for Questions #23 & #24: The first New Zealander to win the Nobel Prize in Chemistry (1908), Ernest Rutherford, is credited with showing that the atom was mostly empty space with most of the mass located at an incredibly dense

central “nucleus.” He did this by shooting high-speed alpha particles,42 He , essentially Helium nuclei, at gold foil. These alpha

particles scattered at various angle due to perfectly elastic collisions with the gold nuclei, 19779 Au . The alpha particles had an

incoming kinetic energy of 138 10x J− . One such alpha particle is pictured below before the collision, Figure #1, and after the collision, Figure #2, with a stationary gold nucleus. The incoming alpha is incident upon the x-axis before the collision. After the

collision, the alpha scatters at 120o with a speed of 71.5 10fmv x s

α = as shown in Figure #2. The gold nucleus has a final speed of

Aufv .

23. Calculate the kinetic energy of the gold nucleus after the collision, AufKE .

(A) 145 10x J− (B) 125 10x J− (C) 137.5 10x J− (D) 138.0 10x J−

24. At what angle below the x-axis does the gold nucleus move after the collision? (A) 10° (B) 30° (C) 60° (D) 120° 25. The graph below represents a variable force F acting on a 16-kg mass that

was initially moving at 4 ms . After the force acts over a displacement of 8-m,

what is the final speed of the mass?

(A) Zero (B) 4.5ms

(C) 20ms (D) 32m

s


PHYSICS I Salmon Test FEBRUARY 14, 2019

SOLUTIONS Corrections: 1. A 14. A 2. C 15. B 3. D 16. A 4. C 17. B 5. D 18. B 6. B All Full Credit Off Topic 19. B 7. D All Full Credit Off Topic 20. D All full Credit 8. A 21. A 9. C 22. D 10. C 23. A 11. C 24. B 12. D 25. B 13. D All Full Credit Off Topic




What is to be mailed back to our office? PLEASE RETURN THE AREA RECORD AND ALL TEAM MEMBER SCANTRONS

(ALL STUDENTS PLACING 1ST, 2ND, 3RD, AND 4TH). If you return Scantrons of alternates, then label them as ALTERNATES.

PHYSICS 1 Salmon Exam Corrections: MARCH 14, 2019

Directions: For each question or statement fill in the appropriate space on the answer sheet. Use the letter preceding the word, phrase, or quantity which best completes or answers the question. Each of the 25 questions is worth 4 points. As prescribed by the College Board for AP Physics, the work done on a system is a positive quantity and gravitational potential energy is defined as zero at an infinite distance. Use g = -10. m/s2.

ADDITIONAL INFORMATION: All axes of rotation are taken to be at the center of mass unless specifically stated otherwise. Rotational Inertia of a solid disc: 2

21 MR Rotational Inertia of a hollow disc (hoop or ring): 2MR

Rotational Inertia of a solid sphere: 2

52 MR Rotational Inertia of a hollow sphere: 2

32 MR

Rotational Inertia of a solid rod of length L with axis of rotation through the geometric center: 2112

ML

Rotational Inertia of a solid rod of length L with axis of rotation through one end: 213

ML

Use the following information for Questions #1 - #4: Since the late ‘70s, New Jersey’s own Six Flags Great Adventure® has hosted a spring Physics Day (started at Columbia HS) where students from several states get their thrills on the rides and then sit down to do some problems. You with mass of 75 kg and your class lab partner of mass 100. Kg. are the only two riders to enter the Swashbuckler™; a ride that isn’t much more than a large round room of diameter D = 10. meters that rotates rapidly, pinning you to the wall. The ride starts from rest. It begins rotating counterclockwise at a constant

angular acceleration of 20.2radsα = as seen from above, which is shown below. Once it reaches a relatively scary

speed, you notice that you are continuing to increase speed. The result is that the angular acceleration does not stop! You continue going faster and faster. Diagrams below are not drawn to relative scale.

1. How long in seconds does it take for you and your partner to break the linear sound barrier? NOTE: The speed of sound in air is 340 m/s. (A) 68 seconds (B) 170 seconds (C) 340 seconds (D) 680 seconds 2. What is the ratio of the centripetal forces (c) acting on you and on your partner at any instant, FC(you)? Fc(partner) (A) 3

4 (B) 11 (C) 43 (D) 3

7

3. Calculate the torque necessary to cause the angular acceleration of 0.2 rad/s2 while you and your partner are on the ride if the floor of the ride is a circular solid disc shape. The circular wall has a mass of 300WallM kg= and the floor is Mfloor = 100. kg

(A) 2

2400 kg ms⋅

(B) 2

2525 kg ms⋅

(C) 2

22,000 kg ms⋅

(D) 2

22,625 kg ms⋅

4. What is the rotational kinetic energy of the system (Ride + You & partner) at the instant you reach the sound barrier? (A) 62.2 10x J (B) 73.0 10x J (C) 87.6 10x J (D) 91.5 10x J

NJSL Phy I March Exam 2019 Page 1

5. As shown below, Def Leppard’s Hysteria album (DL) is initially sitting motionless near the top of a cylindrical spindle and is then dropped on top of the turntable already in motion. The album has a diameter of ( )12 30D inch cm= and

the turntable rotates at an initial 133 3 RPM (Revolutions Per

Minute) with a rotational inertia of 30.60 TI kg m= ⋅ . When the album drops onto the turntable, the turntable slows to 33RPM momentarily until it regains the original

133 3 RPM . What is the mass in grams of the Def Leppard

album? All full Credit. No Answers are correct. (A) 105 grams (B) 135 grams (C) 155 grams (D) 175 grams 6. A child is actively swinging while seated on a backyard swing at the natural frequency of the swing. The child decides to stand up on the swing while maintaining a swinging motion. The frequency of the swing will then (A) decrease. (B) increase. (C) remain the same. (D) depends on the length of the swing rope/chain. 7. A 2.5-m long uniform iron bar of mass 5-kg is hinged at one end through point O and is held motionless at 30o above horizontal, as shown below. After being released, what is the speed of the end of the bar, labeled Point E, as it swings through the lowest point? Assume the hinge is frictionless.

(A) 4.24ms (B) 10.6m

s

(C) 16ms (D) 18m

s

8. Similar to Question #7, the iron bar is replaced by a massless rod of length 2.5-m and a large iron ball of mass 5-kg is attached at the far right end, as shown. After being released, what is the speed of the iron ball at the instant it swings through the bottom-most point?

(A) 3.5ms

(B) 8.7ms

(C) 12.0ms

(D) 15.5ms


Use the following information for Questions #9 & #10: On a game show a contestant gives a wheel, appropriately named the Wheel-of-Fortune, a hard quick shove tangentially to the outside of the wheel with a force of 350N giving it

an initial angular speed of 3.3rads . The Wheel-of-Fortune completes 1.75 full revolutions before coming to a stop.

9. What is the magnitude of the angular acceleration of this Wheel of Fortune while it was slowing down uniformly?

(A) 20.125rads (B) 20.25rad

s (C) 20.50rads (D) 20.75rad

s

10. This Wheel-of-Fortune is basically a solid disc that has a radius of 1.3-m. What is its mass in kg? All Full Credit. No answer is correct. (A) 269 kg (B) 539 kg (C) 808 kg (D) 1077 kg 11. As shown below, two of the famous Three Stooges™ are carrying a heavy uniform horizontal wooden plank on their heads moving at a constant speed to the left. The plank is 5-m long and has a mass of 175-kg. Moe’s head is making contact at the very front end of the plank and Curly’s head is at a point 2-m from the other end. What is the upward force exerted on the plank by both Moe’s and Curly’s heads, respectively?

Moe’s Head Curly’s Head (A) 875 N 875 N (B) 292 N 1,458 N (C) 1,458 N 292 N (D) 350 N 1,400 N

12. While Moe and Curly are walking with the plank on their heads, neither one changing their positions relative to the plank, the other Stooge, Larry, decides to “drop in” near the right (Curly’s) side. What is the minimum distance X from the right end of the plank that Larry of mass 75M kg= can stand without tipping the plank so that both Moe and Curly can continue walking? (A) 0.21 m (B) 0.42 m (C) 0.83 m (D) 1.17 m


Use the following information for Questions #13 - #15: For a physics lab, you construct the apparatus shown below. It consists of a pendulum of length L, a massless string, a pendulum ‘bob” of mass M, a stationary mass of 2M that is attached to an ideal spring of spring constant k. The horizontal surface is frictionless and the “bob” and the mass 2M lightly touch each other as the pendulum hangs motionless as indicated by the dotted lines. The left end of the spring is attached to a solid immovable wall. You raise the bob to a height where is makes an angle of 60o to the vertical and let go. The bob hits the mass 2M perfectly elastically and rebounds with a speed that is 25% of the speed at which it struck the mass 2M. 13. What is the initial speed of the mass 2M immediately after the collision with the bob?

(A) 4gL

(B) 8gL

(C) 5

4gL

(D) 5

8gL

14. How far does the mass 2M move to the left before it comes to rest?

(A) 8

MgLk

(B) 32MgL

k

(C) 58

MgLk

(D) 532MgL

k

15. Assuming the bob is caught and removed immediately after the collision, what is the resulting frequency of oscillation of the mass 2M?

(A) 1

2 2kMπ

(B) 22kM

π (C) 22 M

kπ (D)

1 22

Mkπ

Use the following information for Questions #16 & #17: Bowling balls are returned to the bowler via a long track under the floor. The ball is given an initial speed large enough to successfully make it up a ramp angled upward through the floor onto the “ball return carrousel” with a small enough speed as to not injure the person waiting for it. In this case, an 11-pound (5-kg) ball with a regulation diameter of 8.5-inches (22-cm) requires a final speed at the top of the ball return

ramp of 1fmV s= . Assume the bowling ball is solid and of

uniform density. 16. Assuming the ball rolls without slipping for the entire journey, what initial speed iV must the ball be given in order to attain the desired speed at the top of the ramp?

(A) 4.4ms (B) 5.4m

s

(C) 6.4ms (D) 7.4m

s

17. On a different day the ball return track is freshly greased and the ball slides without rolling for the entire journey. What initial speed iV must the ball be given in order to attain the desired speed at the top of the ramp?

(A) 4.4ms (B) 5.4m

s (C) 6.4ms (D) 7.4m

s


18. Astronauts on the ISS (zero gravity) perform an experiment utilizing a uniform metal rod of mass M and length L that is free to rotate about a point X, as shown below. A blob of clay of mass m is sent toward the free end of the rod at a speed of V. The clay blob strikes and sticks to the end of the rod causing the rod to rotate clockwise around its pivot point X. If

4M m= , what is the speed of the clay blob immediately after striking the rod?

(A) 15

V (B) 14

V

(C) 37

V (D) 73

V

19. The top image below shows a mass M attached to an ideal spring of spring constant k sitting motionless at equilibrium. The equilibrium point is defined as X = 0. The bottom image shows that the mass is then pulled to the right a distance D. It is then released from rest and moves back toward the left. What is the minimum coefficient of kinetic kµ friction that will not allow the mass to move beyond the equilibrium point?

(A) 2kDMg

(B) 2

2kDMg

(C) 2MgkD

(D) MgkD

20. A mass M is attached to a string of length L and is raised to a small angle of θ where it is released from rest and allowed to swing as a pendulum with a resulting frequency of f. If you double all the parameters involved (M, L, and θ), what is the resulting frequency of oscillation in terms of f?

(A) 8 f (B) 8f (C) 2 f (D)

2f

21. A small spider of mass m has crawled inside your CD player and is sitting tightly on the outside rim of a CD of mass M and radius R when you turn on the CD player. The CD starts rotating from rest at a constant angular acceleration of α. How much time, in seconds, does it take for the spider’s tangential acceleration to be equal in magnitude to its centripetal acceleration?

(A) 1α

(B) mMα

(C) 2πα

(D) 2 m

Mπα

22. A lawn roller, pictured below left, is used to compact surfaces of lawns after seeding and other lawn maintenance. A lawn roller consists of a heavy metal cylinder and a handle similar to a lawn mower for the user to push or pull it. The image below right shows a side view of a lawn roller of mass M and radius R being pulled along the ground by a force F. The force F is acting directly at the center of the cylinder and is directed parallel to the ground. The cylinder rolls without slipping. Which of the following expressions represents the frictional force f acting at the surface?

(A) 4F

(B) 3F

(C) 2F

(D) F


23. Below is a diagram of Earth orbiting the Sun in a counterclockwise direction. As Earth travels from aphelion A (farthest point from Sun) to perihelion P (closest point from Sun), which entry in the table below correctly describes what happens to the gravitational potential energy GPE, the linear momentum, and angular momentum of Earth? Diagram not drawn to scale.

24. A complex pulley system is basically two pulleys attached at a common center that will rotate together, as shown below. Mass M is hung from the small pulley of radius r and is larger than mass m which is hung from the larger pulley of radius R. When released from rest, mass M accelerates downward with a magnitude of a. Generally, the masses of the pulleys are considered negligible and they rotate with no friction. However, if the masses of the pulleys are considered in the calculations and friction is still ignored, how does the acceleration of mass M change, if at all, from the first “free” system that accelerates at a? (A) The acceleration of M remains the same. (B) The acceleration of M is increased. (C) The acceleration of M is decreased. (D) The affect cannot be determined without knowing all the numerical parameters. 25. Two different objects are shot straight up into the air by the same mechanism. Upon leaving the mechanism, they both have the same linear momentum. Object 1 has a mass of M while object 2 has a mass of 2M. Object 1 reaches a maximum height of h above the launch site. What is the maximum height reached by object 2?

(A) 4H (B) 2

H (C) H (D) 2H


PHYSICS 1 Salmon Corrections MARCH 14, 2019

SOLUTIONS 1. C 14. D 2. A 15. A 3. D 16. B 4. B 17. C 5. B All full credit 18. C 6. B 19. A 7. B 20. D 8. B 21. A 9. C 22. B 10. D All full Credit 23. B 11. B 24. C 12. C 25. A 13. D




What is to be mailed back to our office? PLEASE RETURN THE AREA RECORD AND ALL TEAM MEMBER ANSWER SHEET

(ALL STUDENTS PLACING 1ST, 2ND, 3RD, AND 4TH). If you return answer sheets of alternates, then label them as ALTERNATES.

PHYSICS 1 Salmon Exam No Corrections APRIL 11, 2019

Directions: For each question or statement fill in the appropriate space on the answer sheet. Use the letter preceding the word, phrase, or quantity which best completes or answers the question. Each of the 25 questions is worth 4 points. As prescribed by the College Board for AP Physics, the work done on a system is a positive quantity, gravitational potential energy is defined as zero at an infinite distance, and use conventional electric current unless specifically stated otherwise. ADDITIONAL INFORMATION: g = -10. m/s2. Fundamental charge: electron = 1.6 x 10-19 C Fundamental charge: Cxe 19106.1 −= Speed of sound in air at 20oC: 340 m/s

1. A rope is tied tightly to a hook anchored to a wall, as shown below. The other end of the rope is “shaken” up and down by a humanoid physics teacher to demonstrate standing waves. The anti-nodes are designated by the A and the nodes are designated by the N. the first three standing wave patterns are shown. If the length of the rope between the teacher’s hand and the anchor point is two meters, which of the following could not represent the wavelenth of a resulting standing wave?

(A) 4m (B) 34

m

(C) 43

m (D) 1233

m

2. You are often told that humans can typically detect sounds that exist between 20 Hz and 20,000Hz . What is this range

in wavelengths of sound in air on a day when the speed of sound in air is 340soundmv s= ?

(A )0.017 m -17 m (B) 0.017 cm – 17 cm (C) 0.059 m – 59 m (D) 0.059 cm – 59 cm

3. The threshold intensity for human hearing at 1000Hz is 1221 10o

WI x m−= . A typical human cannot hear

anything less intense than that. Calculate the sound level in decibels (dB) for a sound having an intensity of 4

25 10 Wx m− (five times as intense as an 80 dB sound)?

(A) 80.5 dB (B) 85 dB (C) 87dB (D) 400 dB 4. Which of the following describes sound waves in air? (A) Purely transverse and speed is independent of frequency. (B) Purely transverse and speed is dependent of frequency. (C) Purely longitudinal and speed is independent of frequency. (D) Purely longitudinal and speed is dependent of frequency. 5. The human auditory canal is essentially a tube open at one end at the outer ear (the pinna) and closed at the other end by the tympanic membrane (the ear drum). The typical auditory canal measures 2.5-cm in length and 0.7-cm in diameter. If the eardrum represented a rigid boundary ( which in reality it does not) what is the fundamental frequency of this typical canal? (A) 34 Hz (B) 3400 Hz (C) 6800 Hz (D) 13,600 Hz 6. For a tube open at both ends and a length of 17-cm, which of the following frequencies cannot be produced by resonance? (A) 500 Hz (B) 1000 Hz (C) 2000Hz (D) 4000 Hz 7. You are driving north in your car at a constant 25 m/s along a straight flat road that happens to be parallel to a railroad track. You are 100-m in front of a train that is moving north at 20 m/s when the engineer sounds the train horn. The horn is designed to emit a loud sound at a frequency of 1000 Hz when the train is stationary. Which of the following choices correctly describes the sound you hear? (A) You hear a sound slightly lower than 1000 Hz in frequency. (B) You hear a sound slightly higher than1000 Hz in frequency. (C) You hear a sound equal to 1000 Hz in frequency. (D) You cannot determine the sound heard without first knowing the speed of sound in air on that day.

NJSL Phy I April Exam 2019 Page 1

8. Two identical neutral, conducting, isolated metal spheres are at rest touching on an isolated tabletop, as shown below in Figure #1. An identical sphere holding a strong net positive charge is brought in from the left and held momentarily near, but not touching, Sphere A, as shown in Figure #2. While the positive sphere remains, Sphere B is moved a short distance away from Sphere A, as shown in Figure #3. Finally, the positive sphere is removed far from the other two, as shown in Figure #4. What are the charge orientations of Spheres A & B as shown in Figure #4? (A) Both spheres are now negative. (B) Both spheres are now positive. (C) Sphere A is negative, Sphere B is positive. (D) Sphere A is positive, Sphere B is negative. Use the following information for Questions #9 & #10: A water molecule, 2H O , is usually depicted by the simplified “Mickey Mouse”™ shape shown below in FIGURE 1. Assume there is a way of stripping all the electrons away so you have only the nuclei remaining in place as shown in FIGURE 2; two hydrogen 1

1 H nuclei and one oxygen 168O nucleus.

Note that the angle between the hydrogen nuclei is 104O and the distance between each 11 H and the 16

8O is 1Å

(Angstrom). 101 1 10Angstrom x m−=

9. What is the magnitude of the net electrostatic force exerted on the oxygen nucleus caused by the hydrogen nuclei? (A) 3.6 x 10-7 N (B) 2.27 x 10-7 N (C) 1.8 x 10-7 N (D) 1.14 x 10-7 N 10. If the three nuclei shown in FIGURE 2 above were each replaced with anti-matter counterparts, what would happen to the direction of the electrostatic force you found in #9 above? Remember that anti-matter particles are real. An anti-proton has the exact mass of a “regular” proton, but an opposite electric charge. Therefore, an anti-proton is simply a proton with a negative charge. An anti-neutron is still a neutron with no net charge. (A) The direction of the electrostatic force changes by 1800. (B) The direction of the electrostatic force remains the same. (C) There is no direction for the electrostatic force since anti-matter particles do not interact electrostatically. (D) The direction of the electrostatic force cannot be determined without first knowing the masses of the anti-particles. 11. At what linear distance is the electrostatic force between two free electrons equal to the weight of one electron? (A) 25 x 10-6 m (B) 5 x 10-6 m (C) 25 m (D) 5 m 12. Which expression below represents the ratio of the electrostatic force to the gravitational force between two charged objects separated by a distance d? Object 1 has a positive charge Q and mass M while Object 2 has a negative charge q and mass m.

(A) 2

kQqGMmd

(B) 2

GMmkQqd

(C) kQq

GMm (D)

GMmkQq

13. Consider the following four measureable quantities in a simple electrical circuit that contains a battery, one resistor, and several conducting wires of non-negligible resistance.

I. The terminal voltage of the battery II. The value in Ohms of the single resistor III. The length of the wires IV. The thickness of the wires

Which of the four quantities listed, when increased independently one quantity at a time while keeping the other three constant, would result in a higher electrical current flowing in the circuit? (A) I & II only (B) I & III only (C) I & IV only (D) I, III, & IV only


Use the following information for Questions #14 - #16: A 60-Watt light bulb is connected in series to a 120-Volt battery as shown below. 14. What is the current flowing through the light bulb? (A) 0.25A (B) 0.50A (C) 1.0A (D) 2.0A 15. If another identical 60-Watt light bulb is now connected in series with the battery and the existing light bulb, what is the current flowing through the battery? (A) 0.25A (B) 0.50A (C) 1.0A (D) 2.0A 16. Starting with the original circuit shown above with just one light bulb, another identical 60-Watt light bulb is now connected parallel to the existing light bulb, what is the current flowing through the battery? (A) 0.25A (B) 0.50A (C) 1.0A (D) 2.0A 17. During a physics lab exercise, your instructor gives you only two resistors. You are then able to construct simple DC circuits that have effective resistances of 3 , 4 , 12 , & 16Ω Ω Ω Ω by using one or both of these two resistors. What are the values of the resistors you are given? (A) 3 & 4 Ω Ω (B) 3 & 16 Ω Ω (C) 4 & 12 Ω Ω (D) 4 & 16 Ω Ω 18. The positive post of a battery with terminal voltage 12TV V= is connected to the positive post of a smaller

6TV V= battery. A circuit is completed by then connecting the negative posts of these two batteries. If each battery has an internal resistance of 1R Ω= , what is the magnitude and direction of the current flowing through the smaller battery? (A) 9 amperes from its positive post to its negative post. (B) 9 amperes from its negative post to its positive post. (C) 3 amperes from its negative post to its positive post. (D) 3 amperes from its positive post to its negative post. 19. Your NJ electricity company charges ten cents per kilowatt⋅hour, kW⋅hr. Note this is not a kilowatt per hour. Your parents are constantly reminding you to turn off the lights in a room when you leave it because, “Money doesn’t grow on trees.” Let us assume you leave your bedroom light on for an entire month of 30-days. The light is a bright 100-W lightbulb operating on the typical 120-V household current. How much cash do you have to pick from that “money tree” to pay for your absent-mindedness? (A) $0.72 (B) $7.20 (C) $72.00 (D) $720.00 20. Two light bulbs are connected in series to a 120-V source. One bulb is rated at 50-W and the other at 100-W. Which statement about the two bulbs must be true? (A) The current through the 50-W bulb is larger than through the 100-W bulb. (B) The current through the 100-W bulb is larger than through the 50-W bulb. (C) The current is the same through each light bulb. (D) The current cannot be determined without first knowing the electrical resistance of each bulb. 21. As shown below, two positive charges are placed on an x-axis with 1 20Q Cµ= located at the origin with the y-axis

and 2 9Q Cµ= is located 3-m to the right of the origin at coordinates (3,0). At what distance d in meters from the origin along the x-axis and between the two positive charges must a negative charge q− be placed so that it is in static equilibrium and will not move once released?

(A) 1.2-m (B) 1.5-m (C) 1.8-m (D) 2.0-m


22. Two identical conducting metal spheres of mass = 100 grams are each given the same electrical charge and then suspended from insulated strings of length, L = 40 cm. After bouncing back and forth like little pendula for a moment, the two spheres come to equilibrium where each string makes an angle of 100 to the vertical. What is the magnitude of the electric charge on each sphere? (A) 76.15 10x C− (B) 73.08 10x C− (C) 62.42 10x C− (D) 61.21 10x C− 23. Given the electrical circuit shown below, what is the current flowing through the battery? (A) 0.5 A (B) 1.93 A (C) 2.00 A (D) 2.94 A 24. You may have heard of Lagrange Points as the “parking spaces” of space. These are specific locations in space where the combined gravitational attractions of two large gravitationally dominant objects like Earth and the Sun cause a third smaller object (a satellite in this case) to have an orbital period, T , of exactly one Earth year. Therefore, the net gravitational forces from the Sun and Earth is the centripetal force acting on the satellite so it orbits the Sun, not Earth. There are five Lagrange Points where we Earthlings “park” observational satellite/probes. They are shown below left labelled L1 through L5. The new Webb Telescope, which will replace the aging Hubble Space Telescope, will reside in L2. Using the diagram above right, which of the following is the appropriate equation that would solve for the distance of L1 from Earth, r? The masses of the Sun, Earth, and satellite are M sun, M Earth, & m respectively. The distance between the Sun and Earth is D . R is the distance from the Sun to the satellite at L1. Assume a circular Earth orbit.

(A) ( )

2 2

2 2 2

4S EM M rG Gr TD r

π− =

− (B)

( )( )2

2 2 2

4S E D rM MG Gr TD r

π −− =

−

(C) 2 2

2 2 2

4S EM m M m RG GR r T

π− = (D)

( )( )22

2 2 2

4S E D RM m M mG GR TD R

π −− =

−

25. The following graph represents the force exerted on a 2-kg mass versus time. The mass is initially at rest at 0t = . What is the speed of the object at t = 6 seconds? (A) 3 m/s (B) 6 m/s (C) 9 m/s (D) 12 m/s


PHYSICS 1 Salmon Exam APRIL 11, 2019 SOLUTIONS

1. B 14. B

2. A 15. A

3. C 16. C

4. C 17. C

5. B 18. D

6. A 19. B

7. A 20. C

8. C 21. C

9. B 22. A

10. B 23. B

11. D 24. B

12. C 25. A

13. C



Phone (cell) # 908-213-8923 Scan then email: [email protected] Web address: http://entnet.com/~personal/njscil/html/

What is to be mailed back to our office? PLEASE RETURN THE AREA RECORD AND ALL TEAM MEMBER ANSWER SHEET

(ALL STUDENTS PLACING 1ST, 2ND, 3RD, AND 4TH). If you return answer sheets of alternates, then label them as ALTERNATES.

AP I and AP 2 PHYSICS FORMULAE Updated 12-17-2018

PHYSICS I Salmon Test Corrections - NJ Science League · 2020-02-02 · s at an angle of 60o above...

Documents

Transcript of PHYSICS I Salmon Test Corrections - NJ Science League · 2020-02-02 · s at an angle of 60o above...