SMDEP Physics

Projectile motion

Ch. 3, #28

0%

100%

0%0%0%0%

1. 1/6 as far2. 6 times as far3. 36 times as far4. 3.4 times as far5. Other6. Didn’t finish

Ch. 3, #32

83%

2% 4%6%4%0%

1. 12.9m2. 129m3. 1.29m4. 38.7m5. Other6. Didn’t finish

Ch. 3, #37

0% 0% 2%0%0%

98%

1. 32.7 s2. 3.27 s3. 5.71 s4. 0 s5. Other6. Didn’t finish

Attendance: What’s your favorite type of music?

19%

13%

42%

8%8%8%

2%

1. Jazz

2. Classical

3. Hip-hop

4. Rock

5. Techno

6. Country

7. American Idol

Survey: How much time are you spending on reading plus homework each day?

4%

28%

2%2%

17%

47%1. 0-1 hour

2. 1-2 hours

3. 2-3 hours

4. 3-4 hours

5. 4-5 hours

6. More than 5 hours

The following graph shows position as a function of time for two trains running on parallel tracks. Which of the following is

true?1. At time T both trains

have the same velocity

2. Both trains speed up all the time

3. Both trains have the same velocity at some time before T

4. Somewhere on the graph, both trains have the same acceleration

posi

tion

time

Train 1

Train 2

T

The following graph shows position as a function of time for two trains running on parallel tracks. Which of the following is

true?

7%0%

93%

0%

1. At time T both trains have the same velocity

2. Both trains speed up all the time

3. Both trains have the same velocity at some time before T

4. Somewhere on the graph, both trains have the same acceleration

For the same graph, compare the trains’ average velocities during the time interval

between t=0 and t=T

33% 33%33%1. <v1> greater than <v2>

2. <v1> less than <v2>

3. <v1> equal to <v2>

posi

tion

time

Train 1

Train 2

T

For the same graph, compare the trains’ average velocities during the time interval

between t=0 and t=T

0 of 7010

33% 33%33%1. <v1> greater than <v2>

2. <v1> less than <v2>

3. <v1> equal to <v2>

The following graph shows the velocity of three objects during the time interval from t1 to t2. All three have the same initial and final velocities. Which object has the greatest velocity over the

entire interval?20% 20% 20%20%20%1. 1

2. 2

3. 3

4. All three have the same average velocity.

5. Cannot tell without knowing the starting positions.

velo

city

time t2t1

1

2

3

The following graph shows the velocity of three objects during the time interval from t1 to t2. All three have the same initial and final velocities. Which object has the greatest velocity over the

entire interval?20% 20% 20%20%20%1. 1

2. 2

3. 3

4. All three have the same average velocity.

5. Cannot tell without knowing the starting positions.

10

0of70

A stone is launched vertically up, and its speed slows under the influence of gravity. Suppose we film this motion and play the

tape backward (so the tape begins with the ball at a high point and ends with the ball at

a low point).

6% 12%

82%1. What you see on the tape could never happen in reality

2. The tape shows the motion of a stone in free fall but the acceleration is upward rather than downward.

3. The tape shows the motion of a stone in free fall with downward acceleration g. 10

0 of 70

A ball is dropped from a cliff (from rest). A second ball is thrown upward

from the cliff, and eventually falls back to where the first ball hit.

7%

40%

33%

20%

1. Both balls have the same speed when they pass the cliff.

2. Both balls hit the ground below with the same velocity.

3. Both balls have the same acceleration.

4. Both balls take the same time to fall starting from when they pass the cliff.

0

70

VOTE

A person standing at the edge of a cliff throws one ball straight up and another straight down at the same initial speed.

Neglecting air resistance, which ball hits the ground with greater speed?

1. The one thrown upward.

2. The one thrown downward.

3. Neither – they hit with the same speed.

4. Not enough information to tell.

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10

A bowling ball is dropped from a building at the same time that a stone is launched upward from the ground. The initial speed of the stone is equal to the speed of the ball just before it hits the ground. The ball and stone

cross: 1. Above2. Exactly at3. Below

..half the height of the building.0 of 70

10

An astronaut stands on the moon where the local acceleration due to gravity, gMoon is 1/6 the value on Earth, gEarth = 9.8 m/s2. If the astronaut drops a golf ball from a certain height, the time it takes to hit the ground

1. Is greater than2. Is equal to 3. Is less than

the time it takes a golf ball on Earth to fall the same distance.

:10

0of70

Consider the following displacement:rr = 6t ii + 4 jj 10 t2 kk

In what direction is the acceleration?

1. + kk

2. - kk

3. In the direction of the vector 6ii20kk

4.4. Can’t tell without a Can’t tell without a lot of algebralot of algebra

5.5. Can’t say without Can’t say without specifying the timespecifying the time

10 SecondsRemaining

0 of 70

Consider the following four situations:1. You make a U-turn at constant speed

2. You drive forward, stop, then go in reverse

3. You make a right turn at constant speed4. You make a right turn and brake while

turningFor which of these situations do you

experience nonzero average acceleration?1. 42. 2 and 43. 24. 1,2, and 45. All of them

10

0of70

Q. Two velocities with magnitudes 3.0 m/s and 4.0 m/s are added. Which of the

following could NOT be the magnitude of their resultant velocity?

60%

0%

10%

30%

1. 3.5 m/s2. 5.0 m/s3. 6.6 m/s4. 7.3 m/s

10

0 of 70

What is the minimum number of forces of equal magnitude that, when added, yield a

vector sum of zero?

1. Five2. Four3. Three4. Two5. One

100 of 70

What is the minimum number of forces of unequal magnitude that, when added, yield

a vector sum of zero?

20% 20% 20%20%20%1. Five2. Four3. Three4. Two5. One

100

0

5

Two penguins are sliding on adjacent paths along the horizontal surface of an iceberg. One moves twice as fast as the other, and they both pass over the edge at the same

instant. Which penguin hits the water first?33% 33%33%

1. The penguin with the faster initial horizontal velocity.

2. The slower penguin.

3. They hit the water at the same time.0

0

70

10

Where do the penguins land relative to each other?

33% 33%33%1. They land in nearly the

same spot because the initial velocity on the iceberg doesn’t affect the subsequent motion.

2. The faster penguin travels further from the iceberg.

3. The slower penguin travels further from the iceberg because it takes longer to fall.

0

70

10