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posted by  CP3 on 7/24/2008 4:24:26 PM  |  status: Closed  

Collision and Impulse

Course Textbook Chapter Problem
Calculus Based Physics Fundamentals of Physics Extended (8th) by Resnick, Halliday, Walker N/A N/A
Question Details:
[HRW8 9.P.028.] In tae-kwon-do, a hand is slammed down onto a target at a speed of 16 m/s and comes to a stop during the 5.9 ms collision. Assume that during the impact the hand is independent of the arm and has a mass of 0.70 kg.
(a) What is the magnitude of the impulse on the hand from the target?
wrong check mark N·s

(a) What is the magnitude of the average force on the hand from the target?
wrong check mark N

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posted by PhysicsCanOnlyBlow on 7/24/2008 4:50:09 PM  |  status: Live
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Response Details:
a) Impulse is equal to mass * change in velocity
So the impulse is 0.7kg * (16m/s - 0m/s) = 11.2 N*s
 
b) Force is equal to mass*acceleration
Acceleration is velocity / time
so a = (16m/s) / (5.9*10^-3s) = 2712 m/s^2
F = m*a = 0.7 * 2712 = 1898.4 N
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