Question

Pam pushes a cart full of bricks (m = 700 kg) with an impulse of 1100 kgm/s, what is the average force she applies to the cart if it starts from rest and she pushes for 8 seconds?

Answer 1

A resultant force causes acceleration and a change in the velocity of the body for as long as it acts. A resultant force applied over a longer time therefore produces a bigger change in linear momentum than the same force applied briefly: the change in momentum is equal to the product of the average force and duration. Conversely, a small force applied for a long time produces the same change in momentum—the same impulse—as a larger force applied briefly.

J= impulse

t2 -t1 = time interval

Faverage = J/ t2- t1

Faverage = 1180/8 = 147.5N

Hence average force is 147.5 N

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