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Unformatted text preview: Homework 9 Slides: 5) E K = (1000kg)(10m/s) 2 = 50,000J , E f K E i K = (1000kg)(1600m 2 /s 2 )  (1000kg)(900m 2 /s 2 ) = (800,000 450,000)J = 350,000J , With traffic more less energy on 95 because 95 would have less traffic and less stop and go. Without traffic US1 would consume less energy because the speed would be less. Acceleration 1 = (10m/s 0)/(10s) = 1m/s 2 ; Force 1 = (1000kg)(1m/s 2 ) = 1000N; Distance 1 = o + t 2 = (1m/s 2 )(100 s 2 ) = 50m; W = (1000N)(50m) = 50,000J , P = E/ = (50,000J)/10s = 5,000W Acceleration 2 = (40m/s 30m/s)/(10s) = 1m/s 2 ; Force 2 = (1000kg)(1m/s 2 ) = 1000N; Distance 2 = o + t 2 = (30m/s)(10s) + (1m/s 2 )(100s 2 ) = 350m; W = (1000N)(350m) = 350,000J , P = E/ = (350,000J)/10s = 35,000W 6) Velocity 1 = ( y 2 + x 2 ); y1 = yo + t, t = d/ x = (10m)/(15m/s) = (2/3)s; y1 = (20m/s) + ( 10m/s 2 )(2/3)s = (60/3)m/s (20/3)m/s = (40/3)m/s; = [(40/3) 2 + (45/3 ) 2 ]m/s = ( 5/3 145 )m/s ; E P = g(h+ h); h = o + t 2 = (20m/s)(6/9)s + (10m/s 2 )(4/9)s 2 = (100/9)m; E P = (5kg)(10m/s 2 )[(100+225)/9]m = 1805.5J , E K = 2 = (5kg)(3625/9)m 2 /s 2 = 1007.0J , W = h( ) = (100/9)(5kg)(10m/s 2 ) = ( 5000/9)J Velocity 2 = x = 15m/s ; E P = mg(h+ h); h = ( f 2 + o 2 )/2 = [(0m/s) 2 + (20m/s) 2 ]/2(10m/s 2 ) = 20m; h = 25m + h = 45m; E P = (5kg)(10m/s 2 )(45m) = 2250J , E K = 2 = (5kg)(15m/s) 2 = 562.5J , W = h( ) = (20m)(5kg)(10m/s 2 ) = 2250J Velocity 3 = ( y 2 + x 2 ); y1 = yo + t, t = d/ x t 2 = (60m)/(15m/s)  (30m)/(15m/s)= 2s; y1 = (0m/s) + (10m/s 2 )(2s) = 20m/s ; = [ (20m/s) 2 + (15m/s) 2 ] = [ 625 ]m/s = 25m/s; E P = mg(h max + h); h = o + t 2 = (0m/s)(2s) + (10m/s 2 )(4s 2 ) = 20m; E P = (5kg)(10m/s 2 )(4520)m = 1250J , E K = 2 = (5kg)(25m/s) 2 = 1562.5J , W = [(h max + h) h ]( ) = [25(4520)]m(5kg)(10m/s 2 ) = 0J Velocity 4 = ( y 2 + x 2 ); y1 = yo + t, t = d/ x t 2 = (70m)/(15m/s)  (30m)/(15m/s)= (8/3)s; y1 = (0m/s) + (10m/s 2 )(8/3)s = (80/3)m/s; = [ ( (80/3) 2 + (45/3 ) 2 ]m/s = (8425/9)m/s ; E P =...
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 Summer '11
 Ramos
 Energy, Work

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