Download Chapter 4 Worksheet

Chapter 4 Worksheet
Name: _______________________
Section: _____________
Date: _________________
Modified True/False
Indicate whether the statement is true or false. If false, change the identified word or phrase to make the statement true.
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1. Energy is the ability to cause change. ________________________________
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2. Energy is measured in joules. ________________________________
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3. When you ride a playground swing, your potential energy is greatest at the highest point. _________
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4. Chemical(Radiant) energy travels from the Sun to Earth and is transformed into light(chemical) energy
by plants. ______
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5. As mass decreases, kinetic energy increases(decrease). _______________________
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6. Lowering an object decreases its potential energy. ______________________
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7. In a car engine, burning fuel produces heat, which causes gases to expand, producing kinetic energy. ___
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8. The sum of potential and kinetic energy in a system is called the total (mechanical) energy.
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9. Carbohydrates and fats provide our bodies with energy in the form of calories. ___________
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10. Energy from the Sun and energy from food are just different forms of the same thing. _______
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11. Energy in the form of motion is potential (kinetic) energy. _________________________
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12. According to the law of conservation of energy, mechanical energy can be changed to heat energy. ____
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13. A rock at the edge of a cliff has kinetic (potential) energy because of its position.
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14. When you put on the brakes of a bicycle, friction causes some of the mechanical energy to change to
thermal energy. _________________________
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15. According to the law of conservation of energy, energy can (cannot) be created or destroyed.
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16. Energy that is stored is kinetic (potential) energy. _________________________
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17. Energy stored in food you eat is chemical potential energy. _________________________
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18. Elastic (mechanical) energy is the total potential and kinetic energy in a system.
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19. Energy is measured in joules. _________________________
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20. Compression (elastic potential) energy is stored in a stretched rubber band.
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21. A book sitting on a shelf has gravitational potential energy. _________________________
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____ 22. The kinetic energy of an object increases as its ____ increases.
a. gravitational energy
c. specific heat
b. potential energy
d. velocity
____ 23. Increasing the speed of an object ____ its potential energy.
a. does not affect
c. decreases
b. increases
d. changes
____ 24. The SI unit for energy is the ____.
a. calorie
c. meter per second
b. joule
d. kilogram
____ 25. You can calculate kinetic energy by using the equation ____.
a. KE (J) = m (kg)  9.8 m/s2  h (m)
c. KE (J) = 1/2 m (kg)  v2 (m2/s2)
b. KE (J) = w (m)  h (m)
d. KE (J) = 9.8 m/s2  1/2 m (kg)
____ 26. You can calculate gravitational potential energy by using the equation ____.
a. GPE (J) = 1/2m (kg)  1/2h (m)
c. GPE (J) = h (m)  9.8 m/s2
b. GPE (J) = m (kg)  9.8 m/s2  h (m)
d. GPE (J) = 1/2h (m)  w (m)
____ 27. Which of the following devices does not make use of electrical energy?
a. piano
c. toaster
b. radio
d. digital camera
____ 28. A bus engine transfers chemical potential energy into ____ so that the bus moves.
a. thermal energy
c. electrical energy
b. gravitational potential energy
d. kinetic energy
____ 29. In a nuclear fusion reaction, mass is transformed into ____.
a. matter
c. energy
b. nuclei
d. light
____ 30. According to the law of conservation of energy, the total amount of energy in the universe ____.
a. remains constant
c. increases
b. changes constantly
d. decreases
Completion
Complete each statement.
31. If an object has energy, this means that the object has the ability to cause change
32. If you double the velocity of an object, you increase its kinetic energy by a factor of 4
33. Stored energy is called potential energy.
34. A fire warms you by transferring thermal energy.
35. On a swing, your potential and kinetic energies change, but your mechanical energy does not.
36. According to the law of conservation of energy, energy can change form but it cannot be created or
destroyed under ordinary conditions.
37. When you move your hand or foot, your body has converted potential energy into kinetic energy.
38. You can determine how much energy various foods can give you by checking their calorie content.
Problem
39. An 18-kg bicycle carrying a 62-kg girl is traveling at a speed of 7 m/s. What is the kinetic energy of the girl
and bicycle?
(m is the mass of the girl and the bicycle.)
40. A 70-kg boy is sitting 3 m from the ground in a tree. What is his gravitational potential energy?
41. A 90-kg ceiling light is suspended 4 m above the floor. What is its gravitational potential energy?
Short Answer
42. When coasting while roller skating, you eventually stop. Why?
Because of friction which converts the mechanical energy into thermal energy.
43. Which body processes are fueled by chemical potential energy?
Metabolism + Breathing
Figure 4-1
44. Which ball in Figure 4-1 has the greatest potential energy? D
45. Which ball in Figure 4-1 has the least potential energy? C
46. Can an object at rest, have energy?
Yes, if it is above the ground then it has potential energy.
47. Is it possible for a ball to have both kinetic energy and potential energy at the same time? Explain.
Yes, if it is moving above the ground.
48. A ball has 100 J of potential energy when it is on a shelf. Explain what happens to the potential energy and
the kinetic energy as the ball falls, and find the amount of kinetic energy the ball has at the instant it hits the
floor.
As the ball is falling, its potential energy is changing to kinetic energy.
As it is about to hit the floor, the KE=100J
49. How does the child's ride on the slide change if the slide is lubricated with water to make it slippery?
The ride will be faster because there will be no friction, so no energy is lost.
50. What kind of energy is stored by green plants? Chemical
potential energy
51. A dump truck, a sports car, and a bicycle are traveling at the same velocity. Compare their kinetic energies.
Largest KE for the truck.
Smallest KE for the bicycle.
C
D
B
B
B
B
A
C
A
D
C
D
C
D
D
C