A bullet of 5 g is fired from a pistol of 1.5 kg. If the recoil velocity of a pistol is 1.5 m/s. What is the velocity of the bullet?
Here we have,
Mass of bullet, m1=5 g=51000 kg = 0.005 kg
Mass of pistol, m2=1.5 kg
Recoil velocity of pistol v2=1.5 m/s
Velocity of bullet v1= ?
Since, before firing, the bullet and pistol are in rest, thus
Initial velocity of bullet, u1=0
And initial recoil velocity of pistol, u2=0
We know that,
(0.005 kg×0)+(1.5 kg×0)=(0.005kg×v1)+(1.5 kg×1.5m/s)
0=(0.005 kg×v1)+(2.25 kgm/s)
0.005 kg×v1=−(2.25 kgm/s)
Thus, velocity of bullet = 450 m/s, here negative sign indicates that bullet moves in the opposite direction of recoiling of the gun.