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Usimov [2.4K]
3 years ago
12

If a boy (m = 25 kg) at rest on skates is pushed by another boy who exerts a force of 500 N on him and if the first boy's final

velocity is 20 m/s, what was the contact time?
Physics
1 answer:
Bond [772]3 years ago
7 0

Answer:

1 second

Explanation:

The impulse exerted on the boy is equal to its change of momentum:

I = \Delta p\\F \Delta t = m \Delta v

where

F = 500 N is the push on the boy

\Delta t is the contact time

m = 25 kg is the mass of the boy

\Delta v = 20 m/s is the change in velocity of the boy

Solving the formula for the contact time, we find

\Delta t=\frac{m\Delta v}{F}=\frac{(25 kg)(20 m/s)}{500 N}=1 s

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