Mr. jenkins accidentally backed his car into a stationary light pole. the collision caused damage to his car's bumper, trunk, and tail light. if the light pole was not moving, how did mr. jenkins' car get damaged?

The reason follows from Newton's third law of motion which states that action and reaction are equal and opposite. That is, for every action there is an equal and opposite reaction. So the reason is because the light pole exerted the same force on the car that the car exerted on the light pole.