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Unit Test — Cumulative exam Answers

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Russ makes the diagram below to organize his notes about how Newton’s first law describes objects at equilibrium.

Question illustration
A
Has a net force of zero
B
Has a velocity of zero
C
Is moving with a constant velocity
D
Is slowing down and coming to rest
22
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The diagram shows a heating curve for a substance.

Question illustration
A
X-Y
B
Y-X
C
W-X
D
X-W
23

A hot air balloon pilot wants the balloon to quickly rise several feet higher so it will be above some trees in the distance. Which best explains how the pilot can make the balloon rise?

A
The pilot can adjust the temperature inside the balloon so it is equal to the temperature of the surrounding air.
B
The pilot can adjust the density of the air inside the balloon so it is equal to the density of the surrounding air.
C
The pilot can decrease the temperature inside the balloon so it is cooler than the surrounding air.
D
The pilot can increase the temperature inside the balloon so it is warmer than the surrounding air.
24

A car with a mass of 1,500 kg requires a centripetal force of 640 N to safely follow a circular curve in the road at 13.4 m/s.

A
31 m
B
77 m
C
421 m
D
860 m
25

The power ratings of several motors are listed in the table.An advertising agency writes marketing material for a new motor (Brand W) that has a power rating of 7,640 W. Which statement comparing the motors can they truthfully use?

Question illustration
A
Brand W motor can finish any job faster than Brand Y motor can.
B
There’s not a more powerful motor available.
C
Brand W motor does more work each second than Brand X or Brand Z.
D
Every second, Brand W motor does 7,640 N of your toughest work.
26

What are the conditions needed for an ideal pendulum? Check all that apply.

A
Gravitational force acts to pull the pendulum’s mass down.
B
The mass of the rod of the pendulum is evenly distributed along the rod.
C
The pivot on which the pendulum swings is frictionless.
D
The pendulum swings through its equilibrium position as a result of inertia.
E
Tension acts downward on the pendulum’s mass.
27

A car moving south speeds up from 10 m/s to 40 m/s in 15 seconds. What is the car’s acceleration?

A
2 m/s2
B
15 m/s2
C
30 m/s2
D
50 m/s2
28

The gravitational force between two objects is 1600 N. What will be the gravitational force between the objects if the distance between them doubles?

A
400 N
B
800 N
C
3200 N
D
6400 N
29

A twirler’s baton is 0.76 m long and spins around its center. The end of the baton has a centripetal acceleration of 47.8 m/s2.

A
0.31 s
B
0.56 s
C
4.3 s
D
70 s
30

The image shows a pendulum that is released from rest at point A.

Question illustration
A
From A to C, kinetic energy is transformed into gravitational potential energy.
B
From C to D, kinetic energy is transformed into gravitational potential energy.
C
From C to E, gravitational potential energy is transformed into kinetic energy.
D
From D to E, gravitational potential energy is transformed into kinetic energy.
31

Jan made a diagram to compare speed and velocity.

Question illustration
A
Is always constant
B
Includes magnitude
C
Has direction
D
Depends on a reference frame
32

A velocity vs. time graph for an object is shown.

Question illustration
A
constant and positive
B
constant and negative
C
changing and positive
D
changing and negative
33

Rosalinda wants to calculate the mass of Earth using Kepler’s laws or Newton’s universal law of gravitation.Which data would allow her to find the mass of Earth?

A
the mass of the Sun and the orbital period of the moon
B
the moon’s orbital period and distance from Earth
C
Earth’s distance from the Sun and the moon’s orbital period
D
Earth’s orbital period and distance from the Sun
34

In which scenario is the greatest amount of work done on a wagon?

A
A force of 55 N moves it 8 m.
B
A force of 60 N moves it 6 m.
C
A force of 50 N moves it 5 m.
D
A force of 40 N moves it 10 m.
35

The energy transfer diagram represents the energy of a light bulb.

Question illustration
A
60 J
B
80 J
C
100 J
D
120 J
36

A crane lifts up two boxes.

Question illustration
A
A free body diagram with two force vectors, the first pointing downward labeled F Subscript g A Baseline, the second pointing upward labeled F Subscript T 1 Baseline.
Option A
B
A free body diagram with three force vectors, the first pointing downward labeled F Subscript g A Baseline, the second pointing upward labeled F Subscript T 1 Baseline, and the third pointing downward labeled F Subscript g B.
Option B
C
A free body diagram with three force vectors, the first pointing downward labeled F Subscript g A Baseline, the second pointing upward labeled F Subscript T 1 Baseline, and the third pointing downward labeled F Subscript T 2.
Option C
D
A free body diagram with three force vectors, the first pointing downward labeled F Subscript g A Baseline, the second pointing upward labeled F Subscript T 1 Baseline, and the third pointing upward labeled F Subscript T 2.
Option D
37

The acceleration due to gravity on Earth is 9.8 m/s2. What is the weight of a 75 kg person on Earth?

A
9.8 N
B
75 N
C
85 N
D
735 N
38

Which best describes the heat that you can feel on the engine of a running car?

A
The heat is unusable and absorbed by the engine.
B
The heat is usable and absorbed by the engine.
C
The heat is unusable and lost to the surroundings.
D
The heat is usable and lost to the surroundings.
39

If all else stays the same, which change could be made to cause an increase in the gravitational force on a space shuttle?

A
increasing the distance of the space shuttle from Earth
B
decreasing the distance of the space shuttle from Earth
C
increasing the universal gravitational constant acting on the space shuttle
D
decreasing the universal gravitational constant acting on the space shuttle
40

What is the kinetic energy of an object that has a mass of 50.0 kg and a velocity of 18 m/s?

A
450 J
B
900 J
C
8,100 J
D
16,000 J

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