37_Physics ProblemsTechnical Physics

37_Physics ProblemsTechnical Physics - 38 Motion in One...

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38 Motion in One Dimension Section 2.6 Freely Falling Objects P2.40 Choose the origin yt == 00 , af at the starting point of the ball and take upward as positive. Then y i = 0, v i = 0 , and ag = = 980 . m s 2 . The position and the velocity at time t become: yyv t a t fii =+ 1 2 2 : yg t t f =− 1 2 1 2 22 s 2 ej and vv a t fi : vg t t f = = s 2 ch . (a) at t = 100 . s : y f = () = 1 2 490 2 .. . ms s m 2 at t = 200 s : y f = = 1 2 9 80 2 00 19 6 2 . s m 2 at t = 300 s : y f = = 1 2 9 80 3 00 441 2 . s m 2 (b) at t = s : v f = = ... ±ms ± s 2 at t = s : v f = = 9 80 2 00 19 6 . s 2 at t = s : v f = = 9 80 3 00 29 4 . s 2 P2.41 Assume that air resistance may be neglected. Then, the acceleration at all times during the flight is that due to gravity, = = s 2 . During the flight, Goff went 1 mile (1 609 m) up and then 1 mile back down. Determine his speed just after launch by considering his upward flight: a yy v v i i 2 20 2 9 8 0 1 6 0 9 178 = di bg :. . m 2 His time in the air may be found by considering his motion from just after launch to just before impact: t a t 1 2 2 : 01 7 8 1 2 2 = −− 2 a f tt The root t = 0 describes launch; the other root,
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This note was uploaded on 12/14/2011 for the course PHY 203 taught by Professor Staff during the Fall '11 term at Indiana State University .

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