Physics Pretend-to-be-Jeopardy. Final Jeopardy 300 500 400 100 Graphing 200 300 400 500 100 200 400...
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Transcript of Physics Pretend-to-be-Jeopardy. Final Jeopardy 300 500 400 100 Graphing 200 300 400 500 100 200 400...
Final Jeopardy
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GraphingGraphing
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PhysicsLife at NSAA
PhysicsLife at NSAA
FantasticForces
FantasticForces
Everyday StuffEveryday Stuff Time to FlyTime to Fly
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600 600 600 600
Everyday Stuff...200
A raindrop falls from the sky. It starts from rest somewhere in the clouds. It hits the floor at 100 m/s. How far did the drop fall?
Everyday Stuff...300Yesterday I saw people on TV trying to sound
smart using this problem: Train A leaves the station traveling at 20 m/s. Train B leaves the station traveling at 35 m/s. Both trains travel at a constant velocity. Stations A and B are 175 m apart. After how many seconds do the trains cross paths, assuming they are traveling to the opposite station?
Everyday Stuff...300 - AnswerWe know that they are at the same location when
the cross, so final positions are equal.A B
xf= xi + vt xf= xi + vt
xi + vt = xi + vt0m + (20m/s)t = 175m + (-35m/s)t
(55m/s)t = 175m
t = 3.18st = 3.18s
Everyday Stuff...400
A student wanted to find out if the temperature of water affected the amount of sugar that would dissolve in it. He put 50 mL of water into each of four identical jars. He changed the temperatures of the water in the jars until he had one at 0°C, one at 50°C, one at 75°C, and one at 95°C. He then dissolved as much sugar as he could in each jar by stirring. What is the relationship being studied?
Everyday Stuff... 600
In Physics, what are the standard units for measuring
1. Time
2. Distance
3. Velocity
4. Acceleration
Everyday Stuff...600 - Answer
1. Time: seconds (s)
2. Distance: meters (m)
3. Velocity: m/s
4. Acceleration: m/s2
Launching Things!300
A diver running at 3.6 m/s dives out horizontally from the edge of a cliff and reaches the water below 2.5 s later. How high was the cliff?
Launching Things!400
A ball player wishes to determine her pitching speed by throwing a ball horizontally from an elevation of 4.0 m above the ground. She sees the ball land 25. m down range. Determine the speed of the ball as it leaves her hand
Launching Things!500
A daredevil tries to jump a canyon of width 10 m. To do so, he drives his motorcycle up an incline sloped at an angle of 15 degrees. What minimum speed is necessary to clear the canyon?
Launching Things!600
A long jumper leaves the ground with an initial velocity of 12 m/s at an angle of 28-degrees above the horizontal. Determine the time of flight, the horizontal distance, and the peak height of the long-jumper.
Launching Things! 600 - Answer
Flight Time: 1.1 seconds Horizontal Distance: 12.2 metersPeak Height: 1.6 meters
click here for solution
Graphing!!!100 - Answer
No… Cyclist B starts ahead. The y-intercept gives his
position at time = 0s… or the start.
Graphing!!!200
Determine the object's average velocity.
Determine the object's position at t = 10
.
posi
tion
(m
)
t (s)
10
20
30
40
2 4 6 8
Graphing!!! 300
Determine the displacement for the first three seconds for each object.
Object W Object J
Graphing!!! 300 - Answer
Object WObject W 9 meters9 meters
Object JObject J 9 meters9 meters
Go figure…. Go figure….
Graphing!!! 400
Po
siti
on
(m
)
Time (s)
Here is a position v. time graph for an object. Would it be more accurate to describe the velocity in terms of average velocity or instantaneous velocity? How would you find the one you choose?
Graphing!!! 400 - Answer
Instantaneous VelocityInstantaneous Velocity
Draw a tangent line at a specific point. The Draw a tangent line at a specific point. The slope of that tangent line will be the slope of that tangent line will be the
velocity at that instant in time.velocity at that instant in time.
Graphing!!! 500Sketch a (1) velocity v. time graph and
(2) acceleration v. time graphx
t
A
B
D
E
F
G
C
Po
siti
on
(m
)
Time (s)
Graphing!!! - 600Assume that the ball does not experience any
change in velocity while it is on a horizontal portion of the rail.
Produce the following graphs:
(1)Position v. Time, (2) Vel. v. Time, (3) Accel. v. Time
Physics Life at NSAA 100
A very scared senior that was just caught ditching is running from Mr. Walker. The student accelerates from rest to a speed of28 m/s in 20 s. (Apparently fear makes you go fast.)
What is the acceleration of the senior?
Physics Life at NSAA 200
A student really needs to use the restroom in class but the teacher won’t let him go for 15 minutes. After the 15 mins are up, the student, starting from rest, accelerates at a rate of 6.0 m/s2.
If the restroom door is 16 m away, how fast will the student be going as he reaches the door?
Physics Life at NSAA 300A dancer is practicing for winter
performance. She has her I-pod in and is not paying attention. Starting from rest, she moves across the stage accelerating at a constant 1.0 m/s2.
She plans on continuing to move that way until the song is over in 6s. The stage is 15m wide. Is she going to fall off the stage?
Physics Life at NSAA 400
A skateboarder is skating at a velocity of 6 m/s when a wheel falls off causing him to slow down at a uniform rate of 0.5m/s2. How fast will he be skating after going an additional 13 meters?
Physics Life at NSAA 400 - Answer
4.8 m/svvff
22= + v= + vii22 + 2a + 2a∆∆xx
Moral of the Story: Take care of your stuff.Moral of the Story: Take care of your stuff.
Physics Life at NSAA 500
A student wants to show off her freshly restored 1967 Shelby Mustang. She burns out of the parking lot going from rest to 36 m/s (≈60mph) in 4 seconds. The car's velocity changes at a constant rate. What is the car’s acceleration? How fast will the car be going 3.0 seconds after it starts?
Physics Life at NSAA 600A guy wants to scare his friend. He drives a
car at a constant speed of 25 m/s directly at his friend, with the intention of stopping just before him. His friend is 150 m away when the driver hits the brakes and beings to accelerate uniformly at a rate of 0.63m/s2. Will the car come to a stop as the driver intended, or should we call an ambulance?
Physics Life at NSAA 600 - AnswerThe friend is safe. (Solve for the distance he went The friend is safe. (Solve for the distance he went
if his final velocity is 0 m/s, his initial velocity is if his final velocity is 0 m/s, his initial velocity is 25 m/s, his acceleration is -0.63 m/s2.)25 m/s, his acceleration is -0.63 m/s2.)
The driver stopped after 99.2 m….. 0.8m short.The driver stopped after 99.2 m….. 0.8m short.
vvff22= + v= + vii
22 + 2a + 2a∆∆xxIf you try to solve for the final velocity at 100m you If you try to solve for the final velocity at 100m you
will end up having to take the square root of a will end up having to take the square root of a negative number (it wont work.. Because he had negative number (it wont work.. Because he had no velocity at 100 m/s)no velocity at 100 m/s)
Forces100
A 4600 kg helicopter accelerates upward at 2.0 m/s2. What lift force is exerted by the air on the propellers?
Forces100 - Answer
54280 N54280 N
FFLL: Force lifting helicopter off ground: Force lifting helicopter off ground
ΣF = FΣF = FLL – F – FEE = ma = ma
FFLL – (4600kg)(9.8N/kg) = (4600kg)(2m/s2) – (4600kg)(9.8N/kg) = (4600kg)(2m/s2)
FFLL = 9200 N + 45080 N = 9200 N + 45080 N
FFLL = 54280 N = 54280 N
Forces 200
A race car has a mass of 710 kg. It starts from rest and travels 40.0m in 3.0s. The car is uniformly accelerated during the entire time. What net force is acting on the car?
Forces 200 - Answer
6305 N6305 N(1) Find Acceleration(1) Find Acceleration
xf = xi + vit + ½ atxf = xi + vit + ½ at22
(2) Find Net Force(2) Find Net Force
ΣF = maΣF = ma
Forces300
A 65 kg person dives into the water from the 10 meter high platform.
a) What is her speed as she enters the water?
b) She comes to a stop 2.0 m below the surface of the water. What net force did the water exert on the swimmer?
Forces400
Suppose that a 1000 kg car is traveling at 25 m/s (≈55 mph). Its brakes can apply a force of 5000N. What is the minimum distance required for the car to stop?
Forces500
A 10 kg block is allowed to slide down a ramp with uk = 0.15.
a. What is the value of the frictional force opposing the block's slide down the ramp?
b. What is the acceleration of the block?
Forces 600
A 70.0 kg box is pulled across a frictionless surface by a 300. N force at an angle of 30.° to the horizontal.
What is the acceleration of the box in the x-direction?
What is the normal force on the box?