A 5.00g lead bullet is fired into a wooden fence post. The initial speed of the bullet is 250m/s, and when it comes to rest, half its kinetic energy goes into heating bullet. How much does the bullet's temperature increase?

Answer 1

The heat capacity of lead is C = .127.10^3J/kg*K (I googled it)
So the heat capacity of the bullet is Cm=.635 J/K
The kinetic energy of your bullet is KE = 1/2*5.10^-3 250^2 J

Therefore the increase in temp will be 1/2KE/(Cm) = 123 degrees