Question

A bullet of mass 20 gram strikes a block of mass 980g with velocity v and is embedded in it.

Answer 1

Mass of the bullet = 20g,
initial Velocity of the bullet = v m/s,

Mass of the block = 980g,
Initial Velocity = 0,

After the collision the block has bullet embedded in it so There will be a combined mass, and the block will move with certain velocity , And this can be calculated by Newton's 3rd Law,

According to Newton's 3rd Law, Momentum is conserved,

So initial momentum = Final momentum,
and Momentum P = m*v,

By this statement we can write that,

20*v + 980* 0 = (20+980)*final velocity,

Let final velocity be a,

I have written (20+980) because bullet is embedded in it , and the whole system is moving with same velocity,

=> 20v = 1000a,
=> a = 20/1000 * v,
=> a = 0.020v,
=> a = 0.02 v,

Therefore the final velocity of the body is 0.02 times the bullet's initial velocity, If you can provide bullet's initial velocity we can find the final velocity of the system !

Hope you understand, Have a great day !