A 6 kg rifle is used to fire a 9 g bullet, which travels with a speed of 700 m/s.
(a) What is the speed of recoil of the rifle?
______m/s
(b) How much energy does it transmit to the shoulder of the person using the rifle as it stops?
______J
I have solved part (a) which is 1.05 m/s but I have no idea how to do part (b)