A lead bullet of mass 10 ~g travelling at 300 ~m / s strikes against a block of wood and comes to rest. Assuming 50 % of heat is absorbed by the bullet, the increase in its temperature is (Specific heat of lead =150 ~J / kg ^ C )

Step-by-step solution

m=10 ~g =10 10⁻³ ~kg , v=300 ~m / s aligned Heat produced = & 1 2 KE of the bullet & = 1 2 ( 1 2 m v^2 ) & = 1 4 10 10⁻³ (300)^2 & =2.5 10⁻³ 9 10^4 & =225 ~J aligned From aligned Q & =m s t 225 & =10 10⁻³ 150 t t & = 225 10 10⁻³ 150 & = 225 1.5 & =150^ C aligned