MPSC Civil Engineering (2020) Booklet Code (D) Q 68 A rifle of 5 kg mass fires a bullet of 10 gm mass at a velocity of 300 m/s. Determine the velocity with which rifle recoils.

 Given :-

Mass of Gun (M) = 5 kg = 5 x 1000 = 5000 gm

Mass of bullet  (m) = 10 gm

Velocity of bullet (v) = 300 m/s

Resolve velocity (V_r) = ?

Solution :-

Law of Conservation of Momentum

               P_i    =     P_f   

( M + m ) V_r  =   m x v

( 5000 + 10 ) V_r  = 10 x 300

                       V_r  = 3000 / 5010

                        V_r   = 0.6 m/s

The velocity with rifle recoils = 0.6 m/s