Unit 2 Practice Test

Question 1

The graph shows the motion of a theoretical particle in a particle accelerator.

Which of the following statements is not correct?

Answer 1

The particle does not experience any instantaneous changes in position

Question 2

Suppose a ball was initially at y0. It then moved in the negative direction and rested for a while. It then moved again in the negative direction. Finally the ball returned to its original position. Which graph best represents the motion of the ball?

Answer 2

-

Question 3

Suppose a train starts at point −3. It moves to point +5, rests, and then proceeds to point +8. Later it moves backwards to point −1, then finally stops at point +1. Which of the following is the displacement for the train and the distance traveled by the train?

Answer 3

None of the above.

Question 4

You are going for a bike ride. You ride down a straight road at a speed of 9.0 mi / hr. Just as you pass the point which is 3.6 miles from your starting point, you develop a flat tire. You get off you bike and walk it to a bike shop 0.5 mile further down the road. The walk to the bike shop takes 12 minutes. What was your average velocity for the entire trip?

Answer 4

6.8 mi / hr

Question 5

The displacement of a particle is shown in the plot. At which of the following points is the instantaneous velocity 0 m / s?

Answer 5

t2, t4, and t6

Question 6

The equation for the instantaneous velocity of a ladybug walking along a taut telephone wire is v = 3/8t^2-2.7 (in cm/s). The distance of the ladybug from the beginning of the write is x = 1/8t^3 - 2.7t + 9 (in cm) What is the difference between the average velocity of the ladybug between 4 and 7 seconds and the instantaneous velocity of the ladybug at 5.5 seconds?

Answer 6

0.29 cm / s

Question 7

The velocity of an object is v = 15t^4 + 7. Which of the following is the position function that describes x as a function of t?

Answer 7

x = 3t^5 + 7t + c

Question 8

Which of the following shows the correct graph for the velocity of an object whose position is described by x = -2t^2 + 6t

Answer 8

-

Question 9

The graph illustrates the motion of an object. Which of the following statements describes the acceleration of the object?

Answer 9

The acceleration is constant.

Question 10

A bead on a wire has an acceleration that is linear with time: a = kt, where k is equal to 0.75 cm / s3 and t is given in seconds. If the bead has an initial velocity of 1 cm / s, what is its velocity 3 seconds after the motion begins?

Answer 10

4.4 cm / s

Question 11

Suppose that the position of an object in motion is defined by the equation x = −3t ^2 + 15t + 5. Which of the following is the correct graph for the velocity of this object?

Answer 11

-

Question 12

Look at the graph of the acceleration of a particle during various stages (A–E). Which of the following correctly describes a possible function for v during the given stage(s)?

Answer 12

In Stage A, the velocity function is −3t.

Question 13

Which of the following is the correct formula for vf  in terms of vi, a, and Δx ?

Answer 13

vf^2 = vi^2 + 2a(delta x)

Question 14

Which of the following statements about motion when there is constant acceleration is not correct?

Answer 14

xf = xi + vi delta t - a(delta t)^2

Question 15

Suppose a sprinter runs a 50 m race with a constant acceleration. The sprinter starts from rest and runs the race in 5 seconds. Which of the following is the sprinter’s final velocity?

Answer 15

20 m / s

Question 16

Suppose you throw an object straight up at an initial velocity of 17 m / s. How long will it take for the object to reach its maximum height?

Answer 16

1.7 s

Question 17

Your cat chases a spider across the floor. Its position is a function of time is r = (1.2m/s)ti + (0.7m + (0.5m/s^2)t^2)j, where the origin is the southwest corner of the floor. Find the average speed of the cat between t = 0.0s and t = 4.0s

Answer 17

2.3 m / s

Question 18

Suppose you are examining the motion of a train
ri = 25mi + 100 mj
rf = -25mi + 125 mj
What is the value for delta r?

Answer 18

delta r = -50 mi + 25 mj

Question 19

The movement of a goldfish in its aquarium is given by the three dimensional equations:
x = 1.2cm + 3.0cm/s t
y = 1.7cm/s^2 t^2 - 1 cm/s t
z = 0.04cm/s^3 t^3
What are the magnitude of the position, velocity, and acceleration vectors at 5.0 s

Answer 19

r = 41.2 cm; v = 16.6 cm/s; a = 3.6 cm/s^2

Question 20

How long will it take for a ball, with initial horizontal velocity of 80 m / s, to hit the ground from a height of 400 m? Also, what is the range of the ball?

Answer 20

t = 9.0 s; range = 720 m

Question 21

Suppose that an object is launched at an angle of 30° at a velocity of 45 m / s. How long will it take for the object to hit the ground?

Answer 21

4.6 s

Question 22

Sue throws Sam the keys to the car. The keys leave Sue’s hand at a height of 1.2 m from the ground and Sam grabs them out of the air at a height of 1.5 m. Sue throws the keys at an angle of 42° relative to the horizontal. The keys are in the air for 1.3 s.

How far apart are Sue and Sam standing? (Assume there is no drag force and that there is no wind.)

Answer 22

9.6 m

Question 23

A ceiling fan has four blades. The distance between the center of the fan and the tip of the blade is 0.75 m. The fan is spinning at 300 rev / min. What is the radial acceleration of the blade tip as a multiple of g ?

Answer 23

75.5g

Question 24

The compass of an airplane indicates that it is flying south at 150 mi/h. There is a constant 40 mi/h wind blowing the airplane west to the east. The velocity of the airplane relative tot he wind is v A,W. The velocity of the airplane relative to the Earth is v A, E. The velocity of the wind relative to the Earth is v W, E. Given this information, what is the correct description for v A, W

Answer 24

v A,W = 155 mi/h in the SW direction

Question 25

You are in an airport and are hurrying to make a connection. You walk on a moving sidewalk to speed up your progress. The moving sidewalk is going 0.8 m / s and it is 50 m long. You walk on the sidewalk at a rate of 2.5 m / s. Assuming you would have walked at the same speed on the ground, how much time did you gain by getting on the moving sidewalk?

Answer 25

4.8 s