# Physics - Momentum Question

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#1
a toy car of mass 0.05kg collides with a brick. just before it hits the brick, its speed is 3ms^-1. it rebounds at two thirds of its speed. the contact time is 0.2 s.

a- calculate the change of momentum of the car in the impact.

b- calculate the average force on the brick during the impact.
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15 years ago
#2
(Original post by nofronting)
a toy car of mass 0.05kg collides with a brick. just before it hits the brick, its speed is 3ms^-1. it rebounds at two thirds of its speed. the contact time is 0.2 s.

a- calculate the change of momentum of the car in the impact.

b- calculate the average force on the brick during the impact.
a)
p before = mv = 0.15kg m/s
p after = mv = -0.10kg m/s

change in p = 0.25kg m/s

b)

f = dp/dt = 1.25N ->
0
#3
(Original post by rts)
a)
p before = mv = 0.15kg m/s
p after = mv = -0.10kg m/s

change in p = 0.25kg m/s

b)

f = dp/dt = 1.25N ->
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