Relative Motion
Relative Motion refers to the motion or speed of any object in respect to a particular point. For example, a ball thrown upward while in a moving object such as a bus, would be travelling the same speed with respect to the bus and would fall again in relation to that speed. If the ball stopped in mid-air instead, the ball would hit the back of the bus before falling to the floor. In this example, the relative motion of the ball was described in respect to the bus. If the driver turned left, the ball would also be moving left even if it was stationary on the floor. If the ball was described in relation to a different point, such as a pedestrian on the sidewalk and the bus was moving at 35 mph, it would be travelling faster than the pedestrian.
