Question

A $60\text{g}$ bullet fired from a $5\text{kg}$ gun leaves with a velocity of $+500\text{m/s}$. Find the velocity with which the gun recoils.

• A. $+1\text{m/s}$
• B. $-6\text{m/s}$
• C. $+6\text{m/s}$
• D. $-1\text{m/s}$

Answer 1

The correct option is B $-6\text{m/s}$

From law of conservation of linear momentum,

$p_i=p_f$

$\Rightarrow m_1{u}_1+m_2{u}_2=m_1{v}_1+m_2{v}_2$

$\Rightarrow 0.06\times 0+5\times 0=0.06\times (+500)+5\times v$

$\Rightarrow v=-6\text{m/s}$

​​​​​​​Hence, option $\left(B\right)$ is the correct answer.