Question

A railway flatcar whose mass together with the artillery gun is 10 tons moves at a speed 6.0 m/s along the x-axis. The gun barrel makes an angle 30 with this axis. A projectile of mass 120 kg leaves the gun at speed 900 m/s, (relative to the gun) in the direction of the flatcar's motion. Find the speed of the flatcar after the gun has been fired. What should the speed of the flatcar be for it to stop after the firing? Neglect friction.

Answer 1

Answer:

Given, intial velocity=V

and intial mass=3m

velocity at which shell of mass m is thrown =12m/s

angle=60

by applying law of conservation of momentum in horizontal direction,

intial horizontal momentum=final horizontal momentum.

(3m) (V)=m(12) cos(60) +0(3m)(V)=m(12)cos(60)+0

\Rightarrow V=2m/s⇒V=2m/s