Question

A gun is mounted on a railroad car. The mass of the car, the gun, the shells and the operator is 50 m where 'm' is the mass of the one shell. If the muzzle velocity of the shell is 200 m/s, the recoil speed of car after second shot is

• A.
• B.
• C.
• D.

Answer 1

The correct option is C

After first shot ,

$\therefore$ Applying law of conservation of momentum'0 = 200 m - 49 m V $\Rightarrow$ v = $\frac{200}{49}$

After second shot ,

$\therefore$ Applying law of conservation of momentum

- 49 mV = - 48 m V' + m(200 - V

$\Rightarrow$ - 200 = - 48 V' + 200 - $\frac{200}{49}$ m /s

$\Rightarrow$ V' = 200 ( $\frac{1}{48}$ + $\frac{1}{49}$) m/s