Task id16720

A railway platform, the mass of which together with the gun M, moves with speed V along the abscissa axis (Fig. 7.2). The gun barrel makes an angle a with this axis. A projectile of mass m flies out of the gun with a speed v relative to the gun in the same direction where the platform is moving. Find the speed of the platform after the shot. At what initial speed will the platform stop after the shot? Ignore friction. Take M=10 t, m=120 kg, V=6.0 m/s, v=900 m/s, a=30°.