H. Physics Chapter 5 Test(2)
50. A medicine ball has a mass of 5 kg and is thrown with a speed of 2 m/s. What is its kinetic energy? a. 10J c. 100J b. 500J d. 2,000 J
A
7. Which of the following energy forms is associated with an object due to its position? a. potential energy c. total energy b. positional energy d. kinetic energy
A
10. A bus engine transfers chemical potential energy into ____ so that the bus moves. a. gravitational potential energy c. electrical energy b. kinetic energy d. thermal energy
B
ball example
The ball begins with maximum potential energy. As the ball rolls down the hill, potential energy is transformed to Kinetic Energy. Kinetic Energy is at its maximum at the bottom of the hill because this is the point where the ball is traveling the fastest.
21. An object weighing 75 N is dropped from the top of a building and falls a distance of 28 m to the ground. How much work does gravity do on the object from the time it is dropped to the time it hits the ground? a. 4,625J c. 75J b. zero d. 2,100 J
D
24. The law of conservation of energy states that energy a. is created from motion. c. can only be converted into heat. b. is always equal and opposite. d. cannot be created or destroyed.
D
27. Increasing the speed of an object ____ its potential energy. a. decreases c. increases b. changes d. does not affect
D
34. The kinetic energy of an object increases as its ____ increases. a. potential energy c. gravitational energy b. specific heat d. velocity
D
35. The transfer of energy to a body by the application of a force that causes the body to move in the direction of the force is called a. mechanical advantage b. distance. c. power. d. work.
D
41. What is the kinetic energy of a 1.40 kg discus with a speed of 22.5 m/s? a. 15.8J c. 31.5 J b. 709J d. 354J
D
47. What is the gravitational potential energy of a 54 kg box that is 8.0 m above the ground? a. 4,300 J c. 550 J b. 5,500 J d. 3,400 J
D
8. Ball A has triple the mass and speed of ball B. What is the ratio of the kinetic energy of ball A to ball B. a. 3 b. 6 c. 9 d. 27
D
1. Work is done when a. the displacement is not zero. b. the displacement is zero. c. the force is zero. d. the force and displacement are perpendicular.
A
11. If the mass in a horizontal mass-spring system was doubled, the elastic potential energy in the system would change by a factor of a. 0 (no change). c. 2. b. 1/2. d. 4.
A
12. What are the units of power? a. Watts b. Newtons c. Joules d. All of the above
A
13. Why doesn't the principle of mechanical energy conservation hold in situations when frictional forces are present? a. Kinetic energy is not completely converted to a form of potential energy. b. Potential energy is completely converted to a form of gravitational energy. c. Chemical energy is not completely converted to electrical energy. d. Kinetic energy is completely converted to a form of gravitational energy.
A
15. The primary source of the sun's energy is a. nuclear fusion. b. nuclear fission. c. potential energy d. chemical energy
A
20. Which of the following processes requires the most work? a. A person lifts a 1 kg weight 1 m off the floor. b. A person holds a 1 kg weight still with outstretched arms. c. A 10 kg ball is rolled across the floor at a constant speed for a distance of 10 m. d. A 10 kg weight rests on a table.
A
22. At the top of its arc, a thrown ball has _____ potential energy. a. maximum c. average b. zero d. minimum
A
25. The kind of energy associated with atomic bonds is a. chemical energy. c. light energy. b. nuclear energy. d. kinetic energy.
A
36. The SI unit for energy is the ____. a. joule b. kilogram c. calorie d. meter per second
A
38. How much power is required to do 180 J of work in 2.4 s? a. 75W c. 7.5W b. 178W d. 430W
A
4. A child moving at constant velocity carries a 2 N ice-cream cone 1 m across a level surface. What is the net work done on the ice-cream cone? a. 0J c. 2J b. 0.5J d. 20J
A
4. Work is done when a. the displacement is not zero. b. the displacement is zero. c. the force is zero. d. the force and displacement are perpendicular.
A
43. Which of the following statements is not true? a. If the kinetic energy of an object decreases, the nonmechanical energy will decrease. b. The energy of a closed system is constant. c. Energy cannot be created or destroyed. d. The energy of an open system can increase.
A
5. The work-kinetic energy theorem states that a. the net work done on an object equals the kinetic energy of the object. b. the net work done on an object equals the change in the kinetic energy of the object. c. the change in the net work done on an object equals the kinetic energy of the object. d. the change in the net work done on an object equals the change in the kinetic energy of the object.
A
16. In a nuclear fusion reaction, mass is transformed into ____. a. matter c. nuclei b. light d. energy
D
The higher the item is from the ground, the more _________________ it has.
potential energy
the energy of an object due to its position, shape, or condition
A. potential energy
12. The main difference between kinetic energy and potential energy is that a. kinetic energy involves position, and potential energy involves motion. b. kinetic energy involves motion, and potential energy involves position. c. although both energies involve motion, only kinetic energy involves position. d. although both energies involve position, only potential energy involves motion.
B
13. _____ is defined as the rate at which work is done. a. Speed b. Power c. Mechanical advantage d. Joule
B
2. What is the common formula for work? Assume that W is the work, F is a constant force, v is the change in velocity, and d is the displacement. a. W=Fv c. b. W=Fd d. W=Fd
B
20. A more powerful motor can do a. more work in a longer time interval. b. the same work in a shorter time interval. c. less work in a longer time interval. d. the same work in a longer time interval.
B
3. A force does work on an object if a component of the force a. is perpendicular to the displacement of the object. b. is parallel to the displacement of the object. c. perpendicular to the displacement of the object moves the object along a path that returns the object to its starting position. d. parallel to the displacement of the object moves the object along a path that returns the object to its starting position.
B
3. Energy associated with a compressed or stretched object is a. kinetic energy. b. potential energy. c. gravitational potential energy. d. elastic potential energy.
B
3. In which of the following scenarios is no net work done? a. A car accelerates down a hill. b. A car travels at constant speed on a flat road. c. A car decelerates on a flat road. d. A car decelerates as it travels up a hill.
B
37. As a dropped penny falls toward the ground, _____ energy is converted to _____ energy. a. kinetic, vibrational c. kinetic, heat b. potential, kinetic d. thermal, potential
B
39. A man pushes a crate along a factory floor by exerting a force of 55 N. If the crate moves a distance of 4.0 m, how much work does the man perform? a. 145 J c. zero b. 220N d. 165N
B
48. Mechanical energy can change to nonmechanical energy as a result of a. heat. c. radiation. b. air resistance. d. None of the above
B
5. A horizontal force of 200 N is applied to move a 55 kg television set across a 10 m level surface. What is the work done by the 200 N force on the television set? a. 550J c. 6000J b. 2000 J d. 11000 J
B
5. What is the common formula for work? a. WFv c. WFd2 b. WFd d. WF2d
B
6. Friction does 400 J of net work on a moving car. How does this affect the kinetic energy of the car? a. The kinetic energy increases by 400 J. b. The kinetic energy decreases by 400 J. c. The kinetic energy decreases by 160 kJ. d. The kinetic energy does not change.
B
7. In which of the following scenarios is no net work done? a. A car accelerates down a hill. b. A car travels at constant speed on a flat road. c. A car decelerates on a flat road. d. A car decelerates as it travels up a hill.
B
7. Which of the following does not affect gravitational potential energy? a. an object's mass b. an object's height relative to a zero level c. the free-fall acceleration d. an object's speed
B
9. Which of the following energy forms is not involved in hitting a tennis ball? a. kinetic energy c. gravitational potential energy b. chemical potential energy d. elastic potential energy
B
energy that lies at the level of atoms and that does not affect motion on a large scale
B. nonmechanical energy
1. In which of the following sentences is work used in the scientific sense of the word? a. Holding a heavy box requires a lot of work. b. A scientist works on an experiment in the laboratory. c. Sam and Rachel pushed hard, but they could do no work on the car. d. John learned that shoveling snow is hard work.
C
10. Which of the following formulas would be used to directly calculate the kinetic energy of a mass bouncing up and down on a spring? a. KE 1kx2 c. KE 1mv2 22 b. KE 1kx2 d. KE 1mv2
C
11. Which of the following is an example of mechanical energy? a. chemical energy b. light energy c. potential energy d. nuclear energy
C
14. A boy exerts an average force of 65 N when he lifts a box 1.2 meters. How much work does he do? a. 54 J b. 66 J d. c. 78J d. 0J
C
18. Friction converts kinetic energy to a. mechanical energy. b. potential energy. c. nonmechanical energy. d. total energy.
C
18. Which of the following statements about work and energy is not true? a. Energy may be defined as the ability to do work. b. When work is done, energy is transferred or transformed. c. Work and energy are always equal. d. Work and energy have the same units.
C
19. How much power is required to lift a 30.0 N chair 0.20 m in 2.0 s? a. 1.0W c. 3.0W b. 12W d. 15W
C
2. Energy stored in the gravitational field of interacting bodies is a. kinetic energy. b. nonmechanical energy. c. gravitational potential energy. d. elastic potential energy.
C
2. In which of the following sentences is work used in the everyday sense of the word? a. Lifting a heavy bucket involves doing work on the bucket. b. The force of friction usually does negative work. c. Sam and Rachel worked hard pushing the car. d. Work is a physical quantity.
C
23. What energy change do these appliances have in common? a. They convert heat energy to electrical c. They convert electrical energy to heat energy. energy. b. They convert electrical energy to mechanical energy. d. They convert mechanical energy to electrical energy.
C
26. When a pitcher throws a softball to a catcher, the vibration of the atoms that make up the softball is _____ energy, while the motion of the ball toward the catcher is _____ energy. a. potential, nonmechanical c. nonmechanical, mechanical b. electrical, thermal d. mechanical, chemical
C
31. A boy pushes on a parked car with a force of 200 N. The car does not move. How much work does the boy do on the car? a. 200 L c. zero b. 200 N d. None of the above
C
32. A pendulum swings back and forth and has a kinetic energy of 400 J at a particular point in its path. Which of the following statements is not true? a. The minimum kinetic energy is zero. b. The potential energy increases when the kinetic energy decreases. c. Both the kinetic and potential energy are decreasing. d. When the kinetic energy is zero, the potential energy will be 400 J greater.
C
33. _____ is a measure of the ability to do work. a. Power b. Respiration c. Energy d. Photosynthesis
C
4. How does the kinetic energy of an object change if the object's speed doubles? a. The kinetic energy decreases to half its original value. b. The kinetic energy doubles. c. The kinetic energy increases by a factor of 4. d. The kinetic energy does not change.
C
42. A system that receives energy from external sources is called a. closed. c. open. b. efficient. d. compound.
C
44. A weightlifter presses a 400 N weight 0.5 m over his head in 2 seconds. What is the power of the weightlifter? a. 25 watts c. 100 watts b. 400 watts d. 100 N
C
46. A dropped racquetball will not return to its original position because a. potential energy is inefficient. b. energy is not conserved. c. some of the mechanical energy is converted to nonmechanical energy d. the mechanical energy is stored up for later bounces.
C
49. Calculate the gravitational potential energy relative to the ground when an 82 kg person climbs to the top of a 2.0 m stepladder. a. 402J c. 1600J b. 330J d. 164J
C
51. According to the law of conservation of energy, the total amount of energy in the universe ____. a. decreases c. remains constant b. changes constantly d. increases
C
6. A child pulls a balloon for 12 m with a force of 1.0 N at an angle 60 below horizontal. How much work does the child do on the balloon? a. -10J c. 6.0J b. -6.0J d. 12J
C
6. In which of the following scenarios is work done? a. A weightlifter holds a barbell overhead for 2.5 s. b. A construction worker carries a heavy beam while walking at constant speed along a flat surface. c. A car decelerates while traveling on a flat stretch of road. d. A student holds a spring in a compressed position.
C
Which of the following are examples of conservable quantities? a. potential energy and length b. mechanical energy and length c. mechanical energy and mass d. kinetic energy and mass
C
17. The brakes on a car exert a frictional force of 6,000 N in getting the car to stop. If the work done by the brakes is 120,000 J in coming to a stop, how many meters does the car travel after the driver applies the brakes? a. 40m c. 6m b. 12m d. 20m
D
19. Which of the following is the rate at which work is done? a. potential energy c. mechanical energy b. kinetic energy d. power
D
the energy due to motion
C. kinetic energy
1. Energy that is due to the motion of an object is a. kinetic energy. b. potential energy. c. gravitational potential energy. d. elastic potential energy.
D
10. What are the units for a spring constant? a.N c. Nm b.m d. N/m
D
11. Which of the following equations expresses the work-kinetic energy theorem? a. MEi MEf c. WKE b. Wnet PE d. Wnet KE
D
12. In the presence of frictional force, a. nonmechanical energy is negligible and mechanical energy is no longer conserved. b. nonmechanical energy is negligible and mechanical energy is conserved. c. nonmechanical energy is no longer negligible and mechanical energy is conserved. d. nonmechanical energy is no longer negligible and mechanical energy is no longer conserved.
D
13. Which form of energy is involved in weighing fruit on a spring scale? a. kinetic energy c. gravitational potential energy b. nonmechanical energy d. elastic potential energy
D
14. Gravitational potential energy is always measured in relation to a. kinetic energy. c. total potential energy. b. mechanical energy. d. a zero level.
D
14. Which of the following is the rate at which energy is transferred? a. potential energy c. mechanical energy b. kinetic energy d. power
D
8. How does the elastic potential energy in a mass-spring system change if the displacement of the mass is doubled? a. The elastic potential energy decreases to half its original value. b. The elastic potential energy doubles. c. The elastic potential energy increases or decreases by a factor of 4. d. The elastic potential energy does not change.
D
8. Which of the following energy forms is associated with an object in motion? a. potential energy c. nonmechanical energy b. elastic potential energy d. kinetic energy
D
What are the units for a spring constant? a. N b. m c. N•m d. N/m
D
Which of the following is a true statement about the conservation of energy? a. Potential energy is always conserved. b. Kinetic energy is always conserved. c. Mechanical energy is always conserved. d. Total energy is always conserved.
D
the sum of an object's kinetic and potential energies
D. mechanical energy
15. How much power is required to lift a 2.0 kg mass at a speed of 2.0 m/s? a. 2.0J c. 9.8J b. 4.0J d. 39J
D?
When you coast in your car without touching the brake pedal, the car eventually stops. Why?
Friction causes the kinetic energy to transfer to thermal energy.
Work diff. from power?
Work is force applied over a distance in the direction of the applie force. Power is work divided by the time it took to complete the work.
