At a crime scene, the forensic investigator notes that the 8.2 g lead bullet that was stopped in a doorframe apparaently melted completely on impact. Assuming the bullet was fired at room temperature (20 degrees celcius), What is the minimum muzzle velocity of the gun that fired the bullet? Anyone have idea on how to get muzzle velocity and what they mean by that? so I figured this to be a latent heat of fusion with the Latent heat constant=25kJ/kg or 5.9kcal. So u apply Q=mcdelt T going from 20 celcius to 0 and then add the heat of fusion Q=mL and you can solve for total heat. How do you go from there to get the muzzle velocity? Could anyone help?