Name:    Quiz: Chapter 5 (Projectile Motion)

Multiple Choice
Identify the choice that best completes the statement or answers the question. All questions are worth 1 point each unless otherwise noted.  Use equation below.  Do all of your work on scratch paper provided, do not write on this test. 1

A ball is thrown straight up and then falls straight back down. When it attains maximum height, the ball’s velocity is
 a. equal to its displacement. b. at its maximum. c. at its minimum. d. equal to its displacement divided by the time.

2

(3 points)
A cannon with a barrel velocity of 120 m/s launches a cannonball horizontally from a tower. Neglecting air resistance, how far vertically will the cannonball have fallen after 2 seconds?
 a. 240 m b. 120 m c. 20 m d. 480 m e. none of the above

3

A vector is a quantity that has
 a. magnitude and time. b. time and direction. c. magnitude and direction.

4

A ball thrown in the air will never go as far as physics ideally would predict because
 a. gravity is acting. b. air friction slows the ball. c. ideally the ball would never land. d. one can never throw the ball fast enough. e. all of the above

5

A projectile launched horizontally hits the ground in 1.5 seconds. If it had been launched with a much higher speed in the same direction, it would have hit the ground (neglecting Earth's curvature and air resistance) in
 a. more than 1.5 s. b. less than 1.5 s. c. 1.5 s.

6

In the absence of air resistance, objects fall at constant
 a. speed. b. velocity. c. acceleration. d. distances each successive second. e. all of the above

7

(2 points) Suppose a small plane can fly at 210 km/h relative to the surrounding air. Suppose also that there is a 20 km/h tailwind. How fast does the plane's shadow move across the ground?
 a. 190 km/h b. 230 km/h c. 5 km/h d. 210 km/h e. 20 km/h

8

(3 points) A cannon with a barrel velocity of 70 m/s launches a cannonball horizontally from a tower. Neglecting air resistance, how far vertically will the cannonball have fallen after 4 seconds?
 a. 80 m b. 70 m c. 1120 m d. 280 m e. none of the above

9

(3 points)
you drop a rock off of a tall building.  It hits the ground in 2.7 seconds.  What what the final velocity?
 a. 26 m/s c. -26 m/s b. -2.6 m/s d. 2.6 m/s

10

The resultant vector that would result from adding vectors A and B would look most like which vector? a. c. b. d. 11

(3 Points)
If the height of the ramp was 0.65m above the floor, how long would it take for the marble to hit the ground after it left the ramp? a. 0.36 seconds c. 0.07 seconds b. 0.13 seconds d. 0.26 seconds

12

(3 Points)
A bike travels at a constant speed of 3.5 m/s for 20 seconds.  How far did it travel?
 a. 0.7 meters c. 70 meters b. 7 meters d. 700 meters

13

(3 points)
In the absence of air resistance, the angle at which a thrown ball will go the farthest is
 a. 45 degrees. b. 15 degrees. c. 30 degrees. d. 75 degrees. e. 60 degrees.

14

(3 points)
You drop a rock off of a tall building.  It takes 8.5 seconds to hit the ground.  How tall is the building?
 a. 42 m c. 710 m b. 35 m d. 350 m

15

(3 points)
You drop a rock off of the top of a 45 m tall building.  How long does it take before it hits the ground?
 a. 0.30 s c. 30 s b. 2.1 s d. 3.0 s

16

In the absence of air resistance, the angle at which a thrown ball will go the farthest is
 a. 45 degrees. b. 60 degrees. c. 75 degrees. d. 15 degrees. e. 30 degrees.

17

A ball is thrown straight upward at 5 m/s. Ideally (no air resistance), the ball will return to the thrower's hand with a speed of
 a. 0 m/s. b. 5 m/s. c. 10 m/s. d. 2.5 m/s. e. There is not enough information to say.

18

At the instant a ball is thrown horizontally with a large force, an identical ball is dropped from the same height. Which ball hits the ground first?
 a. The dropped ball b. Neither. They both hit the ground at the same time. c. The horizontally thrown ball

19

The horizontal component of a projectile's velocity is independent of
 a. the vertical component of its velocity. b. time. c. the range of the projectile.

20

A scalar is a quantity that has
 a. direction. b. time. c. magnitude. d. color.

21

If you added the vectors below, the resultant would look most like which of the following vectors? a. c. b. d. 22

(3 points)
You drop a rock off of the top of a 45 m tall building.  How long does it take before it hits the ground?
 a. 30 s c. 0.3 s b. 2.1 s d. 3.0 s

23

If it takes 2 seconds for the pendulum to swing forward and backwards one time, what is the period (T) of the pendulum? a. not enough information to determine c. 2 seconds b. 4 seconds d. 1 second

24

(2 points) What is the resultant of a 12-unit vector and 16-unit vector at right angles to each other?
 a. 20 units. b. 4 units. c. 28 units. d. none of the above

25

The ____________ is the path of a projectile.
 a. trajectory c. range b. velocity vector d. independant

26

In the absence of air friction, the horizontal component of a projectile's velocity doesn't change as the projectile moves.
 a. Always true b. Always false c. Sometimes true

27

(3 points)
A freely falling object starts from rest. After falling for 9 seconds, it will have a speed of about
 a. more than 450 m/s. b. 450 m/s. c. 90 m/s. d. 9 m/s. e. 45 m/s.

28

In the absence of air resistance, at what other angle will a thrown ball go the same distance as one thrown at an angle of 45 degrees?
 a. 50 degrees. b. 35 degrees. c. 45 degrees. d. 40 degrees. e. 60 degrees.

29

A ball thrown in the air will never go as far as physics ideally would predict because
 a. ideally the ball would never land. b. air friction slows the ball. c. one can never throw the ball fast enough. d. gravity is acting. e. all of the above

30

The horizontal component of a projectile's velocity is independent of
 a. time. b. the vertical component of its velocity. c. the range of the projectile.