Unformatted text preview: /s, vf = 50 m/s and the collision lasts for 14 ms, what is the average force on the driver (m = 80 kg) ? Impulse results from change in momentum: ˆ ˆ p f = mv f cos(−10°)i + sin(−10°) ˆ = ( 3940 kg m/s)i + (−695 kg m/s) ˆ j j ˆ I = Δp = p f − pi = ( −910kg m/s)i + ( −3495kg m/s) ˆ j ˆ ˆ pi = mvi (cos 30°i + sin 30° ˆ ) = ( 4850 kg m/s)i + (2800 kg m/s) ˆ j j ( ) Magnitude of impulse: I = (910kg m/s)2 + (3495kg m/s)2 = 3616kg m/s
I 3616kg m/s = = 2.583 × 105 N 3 Δt 14 × 10 s F (⇒ aavg = avg = 329 g ) m Favg = Elas6c and inelas6c collisions What we have learned: In a closed system, total momentum does not change.’ In other words, within a closed system, the total momentum before is the same as the total momentum aer. We also know that total energy will be conserved. However, some energy can be converted from kine6c energy to poten6al, thermal or internal energy. When two bodies collide, total momentum is conserv...
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 Spring '08
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 Momentum, Δp, V2 Institute for the Unstable Media, the00

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