ch07-p045 - 45. (a) The power is given by P = Fv and the...

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45. (a) The power is given by P = Fv and the work done by G F from time t 1 to time t 2 is given by WP tF v t t t t t d d == z z . 1 2 1 2 Since G F is the net force, the magnitude of the acceleration is a = F / m , and, since the initial velocity is v 0 0 = , the velocity as a function of time is given by vv a t Fm t =+= 0 () . Thus 2 1 22 2 2 21 1 (/ ) d ) ( ) . 2 t t WF m t t F m t t ³ For t 1 0 = and 2 1.0s, t = 2 2 1 (5.0 N) (1.0 s) = 0.83 J. 5 k g W §· = ¨¸ ©¹ (b) For 1 t = and 2 2.0s, t = 2 1 (5.0 N) [(2.0 s) (1.0 s) ] 2.5 J.
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This note was uploaded on 05/17/2011 for the course PHY 2049 taught by Professor Any during the Spring '08 term at University of Florida.

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