Trolley car A is 1000 kg and trolley car B is 1500 kg.

A) Is this an elastic, an inelastic, or a completely/perfectly inelastic collision?
B) What is the velocity of the AB pair after A collides with B?
C) How much did the temperature of the 100 kg steel coupler (originally 293 K) change as a result of the collision? The specific heat of steel is 0.466 J/kg.k