Question

The momentum of a bullet of mass 20g fired from a gun is 10kg.m/s . the kinetic energy of this bullet in kj will be?

Answer 1

P=mv

10=20xV

V=1/2

Now

KE =1/2mv^2

= 1/2x20x1/4

= 2.5

Answer 2

To calculate the kinetic energy of the bullet,with the numerical data mentioned in the question,we have to do following calculations:

According to the law of momentum:

P=MV

V=P/M

V=10/20

V=1/2

And, according to the law of kinetic energy:

KE=1/2MV²

KE=1/2×20×1/4

KE=2.5

So the kinetic energy of the bullet will be 2.5KJ(answer)