A 0.030 kg lead bullet hits a steel plate, both initially at 20?C. The bullet melts and splatters on impact. Assume that 80% of the bullet's kinetic energy goes into increasing its temperature and then melting it.
(a) How much heat is required to increase the temperature of the lead bullet and melt it?
(b) What is the minimum speed the lead bullet must have in order to melt on impact?
(c) What happens to the remaining 20% of the bullet's kinetic energy?