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ATB - PE and KE Review. How much PE and/or KE do the following objects have? A 55kg passenger at the top of the starting hill of Steel Force, 60 m above the ground. That same passenger at the bottom of the hill (h=0) moving at 34 m/s. Physics Chapter 7. Energy, continued…. Work and PE
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ATB - PE and KE Review How much PE and/or KE do the following objects have? • A 55kg passenger at the top of the starting hill of Steel Force, 60 m above the ground. • That same passenger at the bottom of the hill (h=0) moving at 34 m/s.
Physics Chapter 7 Energy, continued…
Work and PE Recall, Work is required to lift objects, which then gives the object gravitational PE Work = a change in PE W = DPE Work and KE When a car speeds up, its gain in KE comes from work being done on it. Work = a change in KE W = DKE Work-Energy Theorem Work is a change in Energy!!! Fd = D(mgh) OR Fd = D(1/2mv2)
Conservation of Energy The Law of Conservation of Energy “Energy can never be created or destroyed; it may be transformed from one form to another, but the total amount of energy never changes.”
Conservation of Energy PE = 274.4 J KE = 0 J TE = 274.4 J PE = 125 J KE = 149.4 J TE = 274.4 J m = 7 kg 4 m PE = 0 J KE = 274.4 J TE = 274.4 J
Problems • Review Questions 2-7, 9-11, 13, 14 • Exercises 2, 7-9, 21