For each system, identify the complementary changes of state and associated energies, and determine whether or not the entropy of the system increases.

(a) A puck slides to a stop on a surface. System: puck and surface.

(b) A compressed spring is released and accelerates a cart on a low-friction track. System: spring and cart.

(c) A projectile is fired from a cannon. System: projectile, cannon, and explosive chemicals.

(d) A hot object and a cold object are placed in contact and reach thermal equilibrium. System: both objects.