Question

A dish of mass 20 grams kept horizontally in our by firing bullets of mass 10 gram each @ 10% if the bullet rebounded with the same speed what is the velocity with which the bullets are fired

Answer 1

Answer:

The answer will be 0.95 m/s

Explanation:

According to the problem the mass of the dish is 20 gm

and the mass of the bullets is 10 gm

the rate of firing the bullets is 10 /s

The downward force = mg = 20/1000 x 9.81 = 0.19N

Let the velocity of the bullet when it is fired u m/s

Therefore the momentum of the bullet is , 10 /1000 u  = 0.01u kg m/s

Therefore the momentum of bullet after rebound = - 0.01u kg m/s

change in momentum = -0.01u-0.01u =-0.02u kg m/s

As the bullet is fire at rate of 10 /s

Therefore, 0.19 = 0.02u x 10

           => u = 0.95 m/s