Q. A bullet of mass $10\ g$ moving with $300\ m/s$ hits a block of ice of mass $5\ kg$ and drops dead. The velocity of ice is
A) $50\ cm/s$
B) $60\ cm/s$
C) $40\ cm/s$
D) $30\ cm/s$
Explanation
(b) Here, mass of bullet $m = 10g = \frac{10}{1000}\ kg$
Mass of ice, $M = 5kg$
According to the conservation of linear momentum, we get
$m \times 300 + M \times 0 = m \times 0 + mv$
$\Rightarrow \frac{10}{1000} \times 300 + M \times 0 = 5v$
$\therefore v = \frac{3}{5} = 0.6\ m/s = 60\ cm/s$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.