1.

Claudia is playing a game called bocce, which involves collisions between balls. She strikes a throws a

970

g ball with a velocity of

7.0

m/s east. This ball strikes a stationary ball that also has a mass of

970

g. After the collision, the seconds ball travels with a velocity of

6.2

m/s east. What is the velocity of the first ball immediately after the collision?

	0.50 m/s
	0 m/s
	0.80 m/s
	6.2 m/s

2.

In order to move some heavy machinery onto a stage, Kevin sets up a ramp. The ramp allows him to move a

510

N piece of sound-equipment with a force of

165

N. What is the mechanical advantage of the ramp Kevin set up?

	0.32
	3.1
	4.5

3.

Lewis is towing a

1140

kg car. His truck pulls with a force of

2880

N, and increases the car's velocity from

0

to

6.4

m/s. How long did Lewis apply the force for to achieve this change in velocity?

	9.9 s
	8.1 s
	2.5 s
	16.2 s

4.

In order to pull a boat out of the water, Leslie is using a hand-crank wheel and axle. The wheel and axle system is

81

% efficient. If it requires

12

,

200

J of work to pull the boat out of the water, how much work will Leslie have to do?

	13 , 600 J
	9880 J
	17 , 000 J
	15 , 100 J

5.

An scissor lift performs

9400

joules of work in a period of

2.4

seconds. How much power is the scissor lift producing?

	3900 W
	22 , 600 W
	450 W
	9400 W

6.

Two cars are about to collide. Car A has a mass of

1240

kg, and is traveling north at a speed of

18.3

m/s. Car B has a mass of

1990

kg, and is traveling south at a speed of

4.00

m/s. When they collide, the bumpers become entangled, and the cars move as a single unit. Immediately after the collision, what will be the velocity of the combined unit?

	9.49 m/s
	3.16 m/s
	5.04 m/s
	4.56 m/s

7.

Which of the following actions would increase the torque in a given situation?

	Increasing the lever arm
	Decreasing the lever arm
	Making the force and lever arm parallel
	Making the force and lever arm perpendicular
	Increasing the force
	Decreasing the force

8.

Tasha is using a wedge to split wood. The wedge gives her a mechanical advantage of

4.8

. How much force will Tasha need to exert, if it requires

770

N of force to split the wood?

	160 N
	990 N
	480 N
	3700 N

9.

Two skydivers are in free fall. One skydiver is moving towards the other. When they collide, they link arms, and travel downward as a single unit. Why type of collision is this?

	Inelastic collision
	This is not a collision
	Elastic collision
	Recoil collision

10.

Harrison is holding on to a tree branch. The branch is angled

15

below horizontal. If Harrison weighs

640

N, and he is holding onto the branch

2.1

m away from the trunk, how much torque is he exerting on the tree?

	350 Nm
	1300 Nm
	770 Nm
	1900 Nm

11.

Wanda is driving a screw into a plank of wood. She does

44.6

J of work on the screw, and the screw does

13.9

J of work on the wood. What is the efficiency of the screw Wanda is using?

	31 %
	77 %
	17 %
	54 %

12.

Explain why a car with a greater mass would need brakes that can exert a greater braking force in order to operate safely.

13.

Two boxes are sliding across a smooth table, in the positive direction. Box A has a mass of

4

kg, and a velocity of

8

m/s. Box B has a mass of

6

kg, and a velocity of

4

m/s. If the boxes were to collide, which of the following sets of velocities would conserve momentum?

	v A = 6 m/s, v B = 6 m/s
	v A = 2 m/s, v B = 10 m/s
	v A = 4 m/s, v B = 8 m/s
	v A = 1 m/s, v B = 10 m/s

14.

Clancy has set up a pulley system to lift a

1400

N air conditioner

9.1

m up. The pulley system is

68

% efficient. If Clancy has to exert a force of

110

N, how much rope will he have to pull to lift the air conditioner?

	170 m
	79 m
	140 m
	13 m

15.

Two balls of clay are launched into the air. One, which has a mass of

0.75

kg, travels north at a speed of

11.0

m/s. The other, which has a mass of

0.40

kg, travels south at a speed of

14.4

m/s. When the two balls collide, they fuse to form a single unit. What is the velocity of the single unit?

	2.1 m/s
	12 m/s
	1.7 m/s
	1.7 m/s

16.

A warehouse worker pushes a

19.1

kg box, increasing its speed from rest to

3.40

m/s. This acceleration occured over a period of

0.933

seconds. How much power did the worker produce?

	118 W
	126 W
	110 W
	103 W

17.

In a recoil collision, the force that pushes the two objects apart must come from within the two objects in order for momentum to be conserved. Give an example that demonstrates how an outside force interfering would allow the momentum of the two objects to not be conserved.

18.

Very large vehicles, such as construction and mining equipment, often have very large steering wheels. How is a large steering wheel valuable in a piece of heavy machinery?

19.

Two people are inline skating on the sidewalk. The first person has a mass of

71

kg, and is skating south at a speed of

3.6

m/s. The second person has a mass of

60

kg, and is skating north at a speed of

4.7

m/s. If these two people were to collide, what would their combined momentum be after the collision?

	26 kg*m/s
	540 kg*m/s
	26 kg*m/s
	540 kg*m/s

20.

Clementine is spinning a merry-go-round. When she pulls on the handle, her force is perpendicular to the radius of the ride. If she pulls with a force of

44

N, and the radius of the merry-go-round is

1.7

m, how much torque did Clementine exert on the ride?

	26 Nm
	49 Nm
	75 Nm

21.

While we usually use the unit of the watt, the horsepower is often used to describe the amount of power produced by an engine. Explain what effect a higher horsepower engine has on the performance of a car. Use the term "kinetic energy" in your explanation.

22.

Clark and Maria and bowling next to each other. Clark rolls a

7.7

kg ball at a speed of

6.3

m/s. If Maria's bowling ball mass a mass of

6.8

kg, how fast will she have to release her ball to have the same momentum as Clark's ball?

	8.1 m/s
	6.8 m/s
	7.7 m/s
	7.1 m/s

23.

A

72

kg runner is traveling south at a speed of

5.1

m/s. What is the runner's momentum?

	14 kg*m/s
	26 kg*m/s
	310 kg*m/s
	370 kg*m/s

24.

Claude is using a wrench to twist a bolt. If he pushes perpendicular to the wrench with a force of

29

N, and the wrench's handle is

24

cm long, how much torque is Claude exerting on the bolt?

	120 Nm
	0.83 Nm
	700 Nm
	7.0 Nm

25.

A trail maintenance crew is blowing up a boulder, to remove it from the trail. When they ignite the charge, the boulder splits in two. One side has a mass of

496

kg, and moves east with a velocity of

0.4

m/s. The other side has a mass of

145

kg. What is the velocity of the

145

kg side after the charge is ignited?

	1.4 m/s east
	0.4 m/s west
	1.4 m/s west
	0.4 m/s east

26.

How long will it take a

35

W motor to perform

115

J of work?

	2.5 s
	4.0 s
	`$3.3 s
	0.30 s

27.

While high efficiency is a goal of most machines, perfect efficiency is not actually attainable. As a result, the work done on the machine is greater than the work the machine outputs. Does this inefficiency violate the law of conservation of energy? Why or why not?

28.

Joshua is pushing a set piece for the school play onto the stage. If he applies a

95

N force for a period of

1.3

seconds, how much will the set piece's momentum change during that period?

	440 kg*m/s
	73 kg*m/s
	54 kg*m/s
	120 kg*m/s

29.

How much work can a

2.24

kW motor perform in a period of

0.33

s?

	6800 J
	98 J
	740 J
	2240 J

30.

Devin and Jeremiah are driving bumper cars. Devin, who is traveling north at

4.5

m/s, is behind Jeremiah, who is traveling north at

1.2

m/s. The total mass of Devin's car is

195

kg, and the total mass of Jeremiah's is 180 kg. Immediately after Devin collides with Jeremiah, Devin's velocity reduces to

0.8

m/s north. What is Jeremiah's velocity immediately after the collision?

What is Jeremiah's velocity immediately after the collision?

	4.9 m/s
	6.3 m/s
	5.2 m/s
	4.0 m/s