posted by Preston .
A car moving at 8 m/s crashes into a barrier and stops in 0.050 s. There is a 19-kg child in the car. Assume that the child's velocity is changed by the same amount as that of the car, and in the same time period. (a) What is the impulse needed to stop the child in N*s?(b) What is the average force on the child in N? (c) What is the approximate mass of an object in kg whose weight equals the force in part (b)?