Question

A bullet mass 20 g is fired horizontally with a velocity of 100 ms-1 from a pistol of mass 1.5 kg .calculate the recoil velocity of the pistol

Answer 1

Change the mass 20g to kg 20/1000 = 0.02 0.02*100/1.5= 1.33m/s

Answer 2

use conservation of linear momentum

MV= -mv where,

M= mass of gun
V= Recoil vel of gun
m=mass of bullet
v= velocity of bullet

V= -mv/M
V= - 0.02*100/1.5
V= -2/1.5= -4/3 m/s