A mass M, initially moving at speed v, collides and sticks to a mass m, initially at

Question:

A mass M, initially moving at speed v, collides and sticks to a mass m, initially at rest. Assume M >> m, and work in this approximation. What are the final energies of the two masses, and how much energy is lost to heat, in:
(a) The lab frame?
(b) The frame in which M is initially at rest?