Test: Work and Energy (Chapter 4)

Multiple Choice Questions

  1. 1. In Physics, work involves which two quantities?

  2. 2. Work done (W) by a constant force F displacing an object by d at an angle θ is defined as:

  3. 3. Work is a ___ quantity.

  4. 4. If the angle θ between force F and displacement d is less than 90°, the work done is:

  5. 5. If the angle θ between force F and displacement d is exactly 90°, the work done is:

  6. 6. If the angle θ between force F and displacement d is greater than 90° (e.g., 180°), the work done is:

  7. 7. The SI unit of work is the:

  8. 8. One Joule (J) is equivalent to:

  9. 9. How much work is done on a pail when a person holds it still while moving forward horizontally?

  10. 10. The area under a force-displacement graph represents:

  11. 11. When calculating work done by a variable force, the path is divided into small intervals where the force is assumed to be:

  12. 12. The total work done by a variable force is found by ___ the work done in each small interval.

  13. 13. Mathematically, the work done by a variable force F acting over a displacement d is accurately represented by the area under the ___ vs ___ curve.

  14. 14. In Fig. 4.7, what is the work done moving the object from x=0 to x=4 m?

  15. 15. In Fig. 4.7, what is the work done moving the object from x=4 m to x=6 m?

  16. 16. The space around the Earth where its gravitational force acts is called the:

  17. 17. When lifting an object of mass 'm' vertically upwards by a height 'h' near the Earth's surface, the work done BY gravity is:

  18. 18. When an object of mass 'm' falls vertically downwards by a height 'h' near the Earth's surface, the work done BY gravity is:

  19. 19. Work done in the Earth's gravitational field between two points is:

  20. 20. A field in which the work done is independent of the path followed is called a:

  21. 21. The work done by gravity along a closed path (starting and ending at the same point) is:

  22. 22. Which of the following forces is non-conservative?

  23. 23. Power is defined as the rate at which ___ is done.

  24. 24. The formula for average power (Pav) is:

  25. 25. Instantaneous power (P) is defined as:

  26. 26. Power can also be expressed as the scalar product of force (F) and velocity (v):

  27. 27. The SI unit of power is the:

  28. 28. One Watt (W) is equivalent to:

  29. 29. A commercial unit of electrical energy is the:

  30. 30. One kilowatt-hour (kWh) is equal to:

  31. 31. Energy is defined as the capacity to do:

  32. 32. The energy possessed by a body due to its motion is called:

  33. 33. The formula for kinetic energy (K.E.) is:

  34. 34. The energy possessed by a body due to its position or state is called:

  35. 35. The formula for gravitational potential energy (P.E.) near the Earth's surface is:

  36. 36. Gravitational potential energy is always determined relative to:

  37. 37. The energy stored in a compressed or stretched spring is called:

  38. 38. The work-energy principle states that the work done on a body equals the change in its:

  39. 39. If a force F acts over a distance d on a mass m, changing its velocity from vi to vf, the work done Fd equals:

  40. 40. Absolute gravitational potential energy is defined as the work done by gravity in moving an object from a point to:

  41. 41. Why can't the formula PE = mgh be used for large distances from Earth?

  42. 42. The absolute gravitational potential energy (U) of a mass m at a distance r from the center of Earth (mass M) is given by:

  43. 43. The negative sign in the absolute potential energy formula U = -GMm/r indicates:

  44. 44. As an object moves further away from the Earth (r increases), its absolute potential energy U = -GMm/r:

  45. 45. Escape velocity is the initial speed required for an object to:

  46. 46. To escape Earth's gravity, the initial kinetic energy of an object must be equal to its:

  47. 47. The formula for escape velocity (vesc) from a planet of mass M and radius R is:

  48. 48. The escape velocity from Earth is approximately:

  49. 49. For a freely falling body (neglecting air resistance), as potential energy decreases, kinetic energy:

  50. 50. In the absence of friction, the relationship between potential energy loss and kinetic energy gain for a falling body is:

  51. 51. If air resistance (friction 'f') is present as a body falls a height 'h', the energy conversion is:

  52. 52. The Law of Conservation of Energy states that:

  53. 53. In many real-world energy transformations, some energy appears 'lost', often converted into:

  54. 54. Energy sources that are not currently in widespread common use but have future potential are called:

  55. 55. Energy from tides is primarily due to the gravitational pull of the:

  56. 56. Tidal power plants generate electricity by using the flow of water between high and low tides to turn:

  57. 57. Energy from ocean waves can be harnessed using devices like 'Salter's duck', which utilizes the ___ motion of floats.

  58. 58. The solar constant (solar energy intensity outside Earth's atmosphere) is approximately:

  59. 59. On a clear day at noon, the solar intensity reaching Earth's surface is approximately:

  60. 60. A solar collector for heating water typically has a ___ surface to absorb radiation.

  61. 61. Devices that convert sunlight directly into electricity are called:

  62. 62. Solar cells are typically made from thin wafers of:

  63. 63. Biomass energy refers to energy derived from:

  64. 64. Ethanol as a biofuel is typically produced from biomass by:

  65. 65. Biogas, mainly methane, is produced by the rotting of biomass in a closed tank called a:

  66. 66. Geothermal energy is heat extracted from:

  67. 67. Sources of geothermal heat include radioactive decay, residual heat, and:

  68. 68. A geyser is a hot spring that intermittently ejects:

Short Answer Questions

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