Answer to Question #87832 in Mechanics | Relativity for maa

Question

A car is initially travelling at 5.0ms-1. It then speeds up, accelerating at 1.2 ms-2 for 4.0 seconds. Explain an action reaction pair that would be experienced in this acceleration.

Answer 1

For example, one pair is force with which wheels act on the ground and the ground acts on the wheels in vertical direction. Another example is force that the tires exert on the road and the force that the road exert on tires in horizontal direction. It may seem that a car must stand still, but remember that the Earth's mass is about 6 000 000 000 000 000 000 000 000 kilograms, and heaviest cars weigh 2000-3000 kilograms, so the momentum the car gives to the planet is so small that the car moves while the momentum the car provides is too small to make the Earth seemingly move.