WORK POWER AND ENERGY
1. Which of the following statements defines work correctly?
- a) Work is the product of force and time.
- b) Work is the transfer of energy.
- c) Work is the displacement of an object.
- d) Work is the force applied to an object.
2. A force of 20 N is applied to an object, and it moves a distance of 5 meters in the direction of the force. What is the work done on the object?
- a) 25 J
- b) 50 J
- c) 100 J
- d) 200 J
3. Work is said to be positive when:
- a) The force and displacement are in the same direction.
- b) The force and displacement are in opposite directions.
- c) There is no displacement.
- d) The force is zero.
4. When a person carries a bag horizontally for a certain distance, the work done by the gravitational force is:
- a) Zero
- b) Positive
- c) Negative
- d) Cannot be determined
5. Power is defined as:
- a) The rate of doing work.
- b) The energy possessed by an object.
- c) The ability to do work.
- d) The force applied to an object.
6. A machine does 150 J of work in 5 seconds. What is the power output of the machine?
- a) 30 W
- b) 35 W
- c) 40 W
- d) 45 W
7. The kinetic energy of an object is given by the formula:
- a) KE = mv
- b) KE = 1/2 mv^2
- c) KE = mgh
- d) KE = mgt
8. Which of the following statements about potential energy is correct?
- a) Potential energy depends on an object's motion.
- b) Potential energy depends on an object's velocity.
- c) Potential energy depends on an object's position.
- d) Potential energy depends on an object's time.
9. What is the absolute potential energy at the highest point of a roller coaster ride?
- a) Maximum
- b) Minimum
- c) Zero
- d) Negative
10. The interconversion of kinetic energy and potential energy occurs in which of the following situations?
- a) A pendulum swinging back and forth.
- b) A stationary car parked on a hill.
- c) A rolling ball on a flat surface.
- d) A stationary object on the ground.
11. According to the law of conservation of energy:
- a) Energy can be created but not destroyed.
- b) Energy can be destroyed but not created.
- c) Energy can neither be created nor destroyed.
- d) All of these
12. The SI unit of work is:
- a) Joule
- b) Newton
- c) Watt
- d) Meter
13. Which of the following is an example of work done on an object?
- a) Pushing against a stationary wall.
- b) Holding a book at rest.
- c) Climbing up a flight of stairs.
- d) Carrying a backpack while walking.
14. The work done by a force on an object is zero when:
- a) The force is zero.
- b) The displacement is zero.
- c) The angle between the force and displacement is 90 degrees.
- d) The object is at rest.
15. The work-energy theorem states that:
- a) The net work done on an object is equal to its change in energy.
- b) The work done on an object is directly proportional to its displacement.
- c) The work done on an object is inversely proportional to its velocity.
- d) The net work done on an object is always positive.
16. An object is lifted vertically against the force of gravity. The work done by gravity is:
- a) Positive
- b) Negative
- c) Zero
- d) Cannot be determined without more information.
17. The work done by a spring is maximum when:
- a) It is compressed.
- b) It is stretched.
- c) It returns to its equilibrium position.
- d) It is at rest.
18. The rate at which work is done is called:
- a) Power
- b) Energy
- c) Force
- d) Velocity
19. Which of the following quantities is a scalar?
- a) Work
- b) Power
- c) Force
- d) Displacement
20. A machine does 200 J of work in 10 seconds. What is the power output of the machine?
- a) 20 W
- b) 30 W
- c) 40 W
- d) 50 W
21. Which of the following equations represents the relationship between work, force, and displacement?
- a) Work = force × displacement
- b) Work = force / displacement
- c) Work = force + displacement
- d) Work = force - displacement
22. The formula for gravitational potential energy is:
- a) PE = mgh
- b) PE = 1/2 mv^2
- c) PE = mgt
- d) PE = Fd
23. In an elastic collision between two objects, which of the following quantities is conserved?
- a) Momentum
- b) Energy
- c) Force
- d) Power
24. The energy associated with the motion of an object is called:
- a) Kinetic energy
- b) Potential energy
- c) Mechanical energy
- d) Thermal energy
25. Which of the following statements about kinetic energy is correct?
- a) Kinetic energy depends on an object's mass.
- b) Kinetic energy depends on an object's velocity.
- c) Kinetic energy depends on an object's position.
- d) Kinetic energy depends on an object's time.
26. The maximum potential energy of a spring occurs when it is:
- a) Compressed
- b) Stretched
- c) Released
- d) At rest
27. The law of conservation of energy states that:
- a) Energy can be created but not destroyed.
- b) Energy can be destroyed but not created.
- c) Energy can neither be created nor destroyed.
- d) Energy can be converted into mass.
28. Which of the following energy sources is non-renewable?
- a) Solar energy
- b) Wind energy
- c) Geothermal energy
- d) Fossil fuels
29. The conversion of thermal energy into mechanical work is exemplified by:
- a) A steam engine
- b) A solar panel
- c) A wind turbine
- d) A hydroelectric power plant
30. The efficiency of an energy conversion process is defined as:
- a) The ratio of useful output energy to total input energy.
- b) The ratio of useful output energy to useful input energy.
- c) The ratio of total input energy to useful output energy.
- d) The ratio of total input energy to total output energy.
31. The formula for calculating power is:
- a) Power = work / time
- b) Power = energy / time
- c) Power = force × distance
- d) Power = mass × acceleration
32. The unit of power in the SI system is:
- a) Watt
- b) Joule
- c) Newton
- d) Kilogram
33. Which of the following devices is an example of a machine?
- a) Pulley
- b) Screwdriver
- c) Hammer
- d) Bicycle
34. Which of the following energy sources is renewable?
- a) Natural gas
- b) Coal
- c) Nuclear power
- d) Solar power
35. The law of conservation of energy applies to:
- a) Mechanical systems only
- b) Closed systems only
- c) Open systems only
- d) All systems
36. The work done by a force can be negative if:
- a) The displacement is negative.
- b) The force is negative.
- c) The angle between the force and displacement is greater than 90 degrees.
- d) The object is at rest.
37. The potential energy of an object at rest on a shelf is:
- a) Zero
- b) Positive
- c) Negative
- d) Cannot be determined without more information.
38. Which of the following statements about gravitational potential energy is correct?
- a) Gravitational potential energy depends on an object's motion.
- b) Gravitational potential energy depends on an object's velocity.
- c) Gravitational potential energy depends on an object's position.
- d) Gravitational potential energy depends on an object's time.
39. The work done by friction on a moving object is always:
- a) Positive
- b) Negative
- c) Zero
- d) Cannot be determined without more information.
40. Which of the following statements about the conservation of energy is correct?
- a) Energy can be created but not destroyed.
- b) Energy can be destroyed but not created.
- c) Energy can neither be created nor destroyed.
- d) Energy can be converted into mass.
41. Which of the following energy sources is considered clean and environmentally friendly?
- a) Natural gas
- b) Coal
- c) Nuclear power
- d) Wind power
42. The process of converting sunlight into electrical energy is called:
- a) Solar power
- b) Geothermal power
- c) Hydroelectric power
- d) Biomass power
43. The total energy of a closed system remains constant according to:
- a) The first law of thermodynamics
- b) The second law of thermodynamics
- c) The third law of thermodynamics
- d) The law of universal gravitation
44. The potential energy stored in a stretched rubber band is an example of:
- a) Elastic potential energy
- b) Chemical potential energy
- c) Nuclear potential energy
- d) Thermal potential energy
45. The conversion of mechanical energy into electrical energy is exemplified by:
- a) A generator
- b) A battery
- c) A solar panel
- d) A wind turbine
46. Which of the following energy sources is associated with air pollution and greenhouse gas emissions?
- a) Natural gas
- b) Wind power
- c) Geothermal power
- d) Coal
47. The rate at which energy is transferred or work is done is called:
- a) Power
- b) Force
- c) Velocity
- d) Energy
48. The formula for calculating gravitational potential energy near the surface of the Earth is:
- a) PE = mgh
- b) PE = 1/2 mv^2
- c) PE = mgt
- d) PE = Fd
49. Which of the following energy sources is associated with the potential for radioactive waste?
- a) Natural gas
- b) Coal
- c) Nuclear power
- d) Solar power
50. The conversion of heat energy into mechanical work is exemplified by:
- a) A heat engine
- b) A solar panel
- c) A wind turbine
- d) A hydroelectric power plant
ANSWER KEY:
- b) Work is the transfer of energy.
- b) 50 J
- a) The force and displacement are in the same direction.
- a) Zero
- a) The rate of doing work.
- a) 30 W
- b) KE = 1/2 mv^2
- c) Potential energy depends on an object's position.
- c) Zero
- a) A pendulum swinging back and forth.
- c) Energy can neither be created nor destroyed.
- a) Joule
- d) Carrying a backpack while walking.
- b) The displacement is zero.
- a) The net work done on an object is equal to its change in energy.
- b) Negative
- a) It is compressed.
- a) Power
- a) Work
- a) 20 W
- a) Work = force × displacement
- a) PE = mgh
- a) Momentum
- a) Kinetic energy
- b) Kinetic energy depends on an object's velocity.
- b) Stretched
- c) Energy can neither be created nor destroyed.
- d) Fossil fuels
- a) A steam engine
- a) The ratio of useful output energy to total input energy.
- a) Power = work / time
- a) Watt
- a) Pulley
- d) Solar power
- c) Open systems only
- b) The force is negative.
- a) Zero
- c) Gravitational potential energy depends on an object's position.
- b) Negative
- c) Energy can neither be created nor destroyed.
- d) Wind power
- a) Solar power
- a) The first law of thermodynamics
- a) Elastic potential energy
- a) A generator
- d) Coal
- a) Power
- a) PE = mgh
- c) Nuclear power
- a) A heat engine
