44. Power
45. Mechanical advantage
46. Time
47. Watts
48. Fulcrum
49. Compound machine
50. Screw
51. Energy
52. KE=1/2mv^2
53. Potential energy
54. Kinetic energy
55. Mechanical energy
56. Non- mechanical
57. Chemical energy
58. Photosynthesis
59. Nuclear fusion
60. Open system
61. Open system
62. Efficiency
63. Heat