AnswersNC-Physical Science CR 2024Unit Test

Unit Test — Unit test Answers

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1
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What is needed for work to be done?

A
A force must push on an object without moving it.
B
A force must pull on an object without moving it.
C
A force must cause an object to move along the same direction as the force.
D
A force must act on an object while an equal force acts oppositely on the object.
2
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Which set of terms best defines what affects kinetic energy and potential energy, respectively?

A
position, gravity
B
gravity, velocity
C
velocity, height
D
height, position
3

A powered winch is used to pull a sailboat to shore. The winch uses a 900 W motor.If the motor is used for 30 s, how much work does it do? (Power: P = W/t)

A
0.03 J
B
30 J
C
960 J
D
27,000 J
4

What is the source of almost all energy on Earth?

A
Earth’s hot core
B
the Sun
C
stored carbon
D
moving water
5

Seema knows the mass of a basketball. What other information is needed to find the ball’s potential energy?

A
the volume and height the ball reaches
B
the volume and shape of the ball
C
acceleration due to gravity and the height the ball reaches
D
acceleration due to gravity and the shape of the ball
6

Simone created a chart to summarize the energy transformations that take place when energy from the wind is used to generate electricity.Which best completes the chart?

Question illustration
A
nuclear energy transformed to electrical energy
B
chemical energy transformed to electrical energy
C
radiant energy transformed to mechanical energy
D
kinetic energy transformed to mechanical energy
7

Adita lifts a book from the floor, carries it across the room, and places it on a high shelf. When is Adita doing work on the book?

A
She does work on the book at no time during this process.
B
She does work only while she carries the book across the room.
C
She does work from the moment she touches the book until she lets it go.
D
She does work as she picks up the book and as she lifts it to the shelf.
8

When a person strikes and lights a match, potential energy in the match is transformed into which types of energy?

A
electrical and thermal
B
thermal and radiant
C
radiant and nuclear
D
nuclear and kinetic
9

Which term is the product of force and distance?

A
power
B
work
C
net force
D
acceleration
10

As a person pushes a box across a floor, the energy from the person’s moving arm is transferred to the box, and the box and the floor become warm. During this process, what happens to energy?

A
It is increased.
B
It is conserved.
C
It is decreased.
D
It is created.
11

If the kinetic and potential energy in a system are equal, then the potential energy increases. What happens as a result?

A
Total energy increases.
B
Stored energy decreases.
C
Energy of motion decreases.
D
Total energy decreases.
12

The table shows information about four students who are running around a track. Which statement is supported by the information in the chart?

Question illustration
A
Autumn has more kinetic energy than Chiang.
B
Mohammed has less kinetic energy than Autumn.
C
Lexy has more kinetic energy than Mohammed.
D
Chiang has less kinetic energy than Lexy.
13

Solar-powered cars use energy from the Sun to work. A panel on the car absorbs light energy from the Sun, which then generates an electric current. This electric current, in turn, allows the car to move. Which shows the correct order of energy transformations that take place in a solar-powered car?

A
electrical, chemical, kinetic
B
electrical, kinetic, radiant
C
radiant, chemical, electrical
D
radiant, electrical, mechanical
14

Awanita is placing items on a shelf that is 200 cm above the ground. She exerts a force of 20 N to lift a box from the floor to the shelf. She does this in 5 s.What is Awanita’s power output? (Power: P = W/t)

A
4 W
B
8 W
C
40 W
D
800 W
15

Which change is an example of transforming potential energy to kinetic energy?

A
changing thermal energy to electrical energy
B
changing mechanical energy to chemical energy
C
changing nuclear energy to radiant energy
D
changing radiant energy to electrical energy
16

Power is measured in which unit?

A
joules
B
watts
C
meters per second
D
newtons per meter
17

Plants are responsible for a very important energy transformation, as shown.

Question illustration
A
radiant to chemical
B
nuclear to mechanical
C
chemical to thermal
D
mechanical to chemical
18

Sierra did 500 J of work to move her couch. If she exerts 250 N of force on the couch, how far did she move it? (Work: W = Fd)

A
0.5 m
B
2 m
C
250 m
D
750 m
19

The diagram shows a person holding a bow and arrow.

Question illustration
A
pulling farther back on the string
B
releasing the string
C
holding the arrow higher
D
decreasing the mass of the arrow
20

The table shows information about four objects resting at the top of a hill. Which object is on the tallest hill?

Question illustration
W
W
X
X
Y
Y
Z
Z

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