Q1. A child is sliding on a sled at 1.6 {rm m/s} to the right. You stop the sled by pushing on it for 0.80 {rm s} in a direction opposite to its motion. If the mass of the child and sled is 41 {rm kg}, what average force do you need to apply to stop the sled? Use the concepts of impulse and momentum.

Q2. A rifle with a barrel length of 56 fires an 8 bullet with a horizontal speed of 350. The bullet strikes a block of wood and penetrates to a depth of 14. (a) What resistive force (assumed to be constant) does the wood exert on the bullet? (b) How long does it take bullet to come to rest after entering the wood?