A bullet of mass 20 g moving with a velocity of 500 m/s, strikes a free and goes out from the other side with a velocity of `400 m//s.` Calculate the work done by the bullet in joule in passing through the tree.

Explanation

Here, mass of the bullet, m =20 g = 0.02 kg
initial velocity of the bullet, `u = 500 m//s`
final velocity of the bullet, `upsilon = 400 m//s`
If W is the work done by the bullet in passing through the tree. Then according to work-energy theorem,
`W =(1)/(2)mu^2 -(1)/(2) mv^2 =(1)(2) m (u^2 - upsilon^2)`
`W =(1)/(2) (0.02kg)[(500m//s)^2 -(400m//s)^2] = 900 J`