Question

A gun fires a small bullet with kinetic energy $K$.Then kinetic energy of the gun while recoiling is

• A. $K$
• B. more than $K$
• C. less than $K$
• D. $\sqrt{K}$

Answer 1

Answer: (C)

less than $K$

Answer 2

After firing, the momentum of gun and bullet is same. Therefore, by the relation,
$K=\frac{p^{2}}{2\, m},$ we have
$K \propto \frac{1}{m}\,\,\,\,\,\,\,\,\,\,$(as p is same)
Hence, as the mass of gun is greater, its kinetic energy will be less.