Question

A bullet of mass 100 grams is fired with a velocity of 10 m sec-1 from a gun of mass 1 kg. The ratio of KE of bullet to that of gun is

Answer 1

Forward momentum of bullet = Backward momentum of gun

Mb Vb = Mg Vg

0.1(10) = 1 Vg

Vg = 1 m/s. (recoil velocity)

Ratio of KE

K₁/K₂ = (Vb²/Vg²)(Mb/Mg)

K₁/K₂ = 100(0.1/1)

K₁/K₂ = 10