A bullet of mass 2.5 g moving with a velocity of 500 `ms^(-1)` enters a wooden block and comes out of it with a velocity of 100 `ms^(-1)`. Find the work done by the bullet while passing through the wooden block.

Explanation

Mass `m = 2.5 g = 2.5 xx 10^(-3)` kg, Initial velocity u = 500 m/s , Final velocity v = 100 m/s
By work energy theorem, `W = (1)/(2) m u^(2) - (1)/(2) mv^(2) = (1)/(2) xx 2.5 xx 10^(-2) [(500)^(2) - (100)^(2)]`
`= 1.25 xx 10^(-3) xx 10^(4) [25 - 1] therefore` Work done = 300 J