Question

A bullet of mass $10g$ moving with $300m/s$ hits a block of ice of mass $5kg$ and drops dead. The velocity of ice is

• A. $50cm/s$
• B. $60cm/s$
• C. $40cm/s$
• D. $200cm/s$

Answer 1

The correct option is B

$60cm/s$

Step 1: Given data

Mass of bullet, $m_1=10g$

Initial velocity of bullet, $u_1=300m/s$

Final velocity of bullet, $v_1=0m/s$

Mass of ice, $m_2=5kg$

Initial velocity of ice, $u_2=0m/s$

Final velocity of ice $=v_2$

Step 2: Find the velocity of ice

According to law of conservation of linear momentum

$$\begin{gathered} m_1{u}_1+m_2{u}_2=m_1{v}_1+m_2{v}_2 \\ {10}^{-2}x300+5x0={10}^{-2}x0+5v_2 \\ {v}_2=\frac{3}{5}m/s \\ {v}_2=60cm/s \end{gathered}$$

Hence, option B is correct.