Question

from a rifle of mass 4 kg A bullet of mass 50 gram is fired with an initial velocity of 35 M per second calculate the recoil velocity of rifle

Answer 1

initial mass of rifle m1 = 4 kg

let initial velocity of recoil of rifle = v1

:- initial momentum of the rifle = 4 kg × v1

initial mass of bullet m2 = 50 g

= 50/1000 kg = 0.05 kg

initial velocity of bullet v2 = 35 m/s^-1

:-initial momentum of bullet = 0.05kg × 35m/s^-1

by the law of conservation of momentum,

momentum of bullet = m1v1 + m2v2 =0

m1v1 = m2v2

4kg×v1 = -0.05 kg × 35 m/ s^1

v1 = 0.05×35/4 m/s^-1

= 0.4375 m/ s^-1

I HOPE IT HELPS YOU!!!

Answer 2

$\underline{ \underline{ \bf{Answer}}} : - \\ \implies \: \bf{recoil \: velocity \: = 0.44 \: \frac{m}{s} } \\ \\ \underline{\underline{\bf {Step - by - step \: explanation}}} : - \\ \\ \underline{\bf{ To \: find}} - \\ \\ \bf{find \: recoil \: velocity \: of \: rifle} \\ \\ \underline{\bf{Solution}} : - \\ \\ \bf{velocity \: of \: \: bullet \:( v1) = 35 \: \frac{m}{s} } \\ \\ \bf{ mass \: of \: bullet \: (m1) = 50 \: g = 0.050 \: kg} \\ \\ \bf{mass \: of \: rifle \: (m2) = 4 \: kg } \\ \\ \bf{recoil \: velocity \: of \: rifle \: (v2) =? }$

Since,No external force acts on the rifle then the change in momentum is zero.

Momentum of rifle = (momentum of bullet)

$\implies \: \bf{m2 \: v2 = m1 \: v1} \\ \\ \implies \: \bf{4 \times v2 = 0.050 \times 35} \\ \\ \implies \: \bf{v2 = 0.44 \: \frac{m}{s} } \\ \\ \bf{recoil \: velocity \: of \: rifle \: is \: 0.44 \: \frac{m}{s} }$