Consider the following situations: a car is moving along a straight road at a constant speed. a car is moving along a straight road while slowing down. a car is moving along a straight road while speeding up. a hockey puck slides along a smooth (i. e., frictionless) icy surface. a hockey puck slides along a rough concrete surface. a cockroach is speeding up from rest. a rock is thrown horizontally; air resistance is negligible. a rock is thrown horizontally; air resistance is substantial. a rock is dropped vertically; air resistance is negligible. a rock is dropped vertically; air resistance is substantial.