# physics

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A motor car in rectilinear motion steadily decelerates to rest in 20s.Using Newton's second law of motion,explain why a higher force is required to stop the car in 10s than in 20s.

• physics -

Acceleration is velocity change DIVIDED BY time.

Stopping in less time requires greater acceleration, a.
F = m a
So it also requires more force. Twice as much, in this case.

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