Ex_power-wkeq - Power Average power: Pave = Instantaneous...

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Power Average power: ave W P t = Δ Instantaneous power: t dW PF dt F υ === i G G P = F υ if force and velocity have the same direction, P = F υ if they have opposite directions. Example The 5 Kg cart slides up the frictionless 30 ° ramp under the action of a horizontally applied force F as shown. The cart starts from rest and moves with a constant acceleration of 0.5 m/s 2 from A to B . Find the average power by F for the motion from A to B . Find the instantaneous power of F when the cart reaches point B . ( Ans : P ave = 27 W, P B = 54 W) 4 m F A B Work-kinetic energy equation 2 11 2 2 1 1 2 2 KW K m W m 2 2 2 −− += : Motion of the body is from position 1 to position 2 K = (1/2)
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