A missile is fired form the back of a stationary truck. The missile takes off at a speed of 41.7 m/s and has a mass of 53.8 kg. If the truck has a mass of 856 kg, what is the recoil speed of the truck?

Answer 1

If you fired it straight up, the truck would not move.
If you fired it straight back and there were no brakes on the truck then
53.8 (41.7) = (856-53.8) v