Alead bullet of mass 10 g traveling at 800 m/s, hits a lead block of mass 2 kg at rest and becomes embedded. the combined system now moves with a velocity of about 4 m/s. both the bullet and the block are initially at 25°c. stored energy of the combined system remains constant during the collision. determine the change in temperature of the combined system, assuming the system achieves a uniform temperature quickly after the collision and that there is no heat loss to the surroundings. determine the entropy change of the combined system.