A car moving at 10 m/s crashes into a barrier and stops in 0.050 s. There is a 20 kg child in the car. Assume that the child's velocity is changed by the same amount as the car's, in the same time period. a) What impulse is needed to stop the child? b) What is the average force on the child due to the impulse you found in a)? c) What is the approximate weight in pounds of the force you found in b)? d) Could you lift such a weight with your arms? e) Why is it advisable to use a proper infant restraint rather than hold a child on your lap?