Unit
Test B
Name
Date
Work, Power, and Efficiency
Circle the best answer for each question.
1. Study this drawing of a pulley system.
When Alberto pulls down on the pulley rope, what will happen?
A. The block will go down.
B. The block will go up.
C. The block will not move.
D. The block will move to the left.
2. It takes 500 J for a mountain climber to lift a heavy backpack
up a steep cliff. What would be the amount of work done on the
backpack if the mountain climber uses a set of pulleys to lift it?
A. 0 J
© McGraw-Hill Education
B. less than 500 J
C. exactly 500 J
D. more than 500 J
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Unit 6 • Work, Power, and Efficiency
Use with Unit 6
Name
Unit
Test B
Date
3. Which is not related to the mechanical advantage of a lever?
A. the mass of the load
B. the volume of the load
C. the distances of the load and effort to the fulcrum
D. the force that must be applied
4. Ronny watches a backhoe digging a ditch. “I could do the same
amount of work by hand,” he says. What would be the major
difference between the way the backhoe and Ronny dig?
A. The backhoe can do more work.
B. The backhoe uses more power.
C. The backhoe uses more force.
D. The backhoe loses energy as heat.
5. The efficiencies of several objects are shown in the table below.
Object
Efficiency
Electric fan
Human muscle
Car motor
70 percent
25 percent
17 percent
Which can be concluded about the efficiency of the objects
based on information in the table?
A. Larger objects are more efficient.
© McGraw-Hill Education
B. Heat is not related to efficiency.
C. Less heat escapes objects that are more efficient.
D. More efficient objects lose more heat.
Unit 6 • Work, Power, and Efficiency
Use with Unit 6
107
Unit
Test B
Name
Date
6. Mr. Soto’s science class will measure the amount of work done
by moving a box to different places around the classroom.
Which is a tool they will least likely use to measure work?
A. meterstick
B. spring scale
C. ruler
D. stopwatch
7. The diagram below shows a mover pushing a box up a ramp.
100
N
1 Meter
If the total amount of work is the same with or without the
simple machines shown, why does the mover use the simple
machines?
A. The ramp reduces the mechanical advantage of the mover.
B. Using a ramp prevents energy loss due to friction.
C. The ramp reduces the distance the mover has to climb.
D. The ramp reduces the amount of force the mover has to use
to lift the object.
8. Which explains how work and power are related?
© McGraw-Hill Education
A. Work is the amount of power that is used in a certain
amount of time.
B. Power is the amount of work that is done in a certain
amount of time.
C. You do less work with more power.
D. Power is the amount of work that is done over a certain
distance.
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Unit 6 • Work, Power, and Efficiency
Use with Unit 6
Name
Unit
Test B
Date
9. Terry does 1,000 J of work pedaling her bicycle. The bicycle
does 750 J of work. What is the efficiency of her bicycle?
A. 25 percent
B. 75 percent
C. 125 percent
D. 250 percent
10. Which has the greatest mechanical advantage?
A. a pulley that raises a 600 N bale of hay with a force of 100 N
B. a lever that moves a 250 N load of books with a force of 50 N
C. a moveable pulley with a single wheel
D. a jack that lifts a 1,000 N car with a force of 10 N
11. Roberto experiments with different pulley systems to lift a crate
weighing 100 N. He notices that with a single fixed pulley, 100 N
is needed to lift the crate. He notices that as more pulleys are
added and more loops of rope are added to the systems, the
force needed to lift the crate becomes less. What can he
conclude?
A. The number of loops of rope through the pulley increases
the mechanical advantage.
B. The number of pulleys increases the force needed to lift the crate.
C. The length of rope increases the mechanical advantage.
© McGraw-Hill Education
D. The length of rope increases the force needed to lift the crate.
12. In which of these situations is work done?
A. Chris studies for a test.
B. Mario holds a book in his hands.
C. Ana pushes against a locked door.
D. Armando throws a baseball 15 ft.
Unit 6 • Work, Power, and Efficiency
Use with Unit 6
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