Question

(b) (i) state newton’s third law of motion. (ii) a stone falls towards the earth but the earth does not move up towards the stone. state, with reasons, whether newton’s third law is obeyed in this case. 5

Explanation:

(i) Newton's third law states that for every action, there is an equal and opposite reaction. The forces act on two different objects.
(ii) Newton's third law is obeyed. The stone exerts a force on the earth equal in magnitude to the force the earth exerts on the stone. However, the earth has a much larger mass than the stone. According to Newton's second law ($F = ma$), for the same force, the acceleration of the earth is extremely small (negligible) compared to the acceleration of the stone due to its large mass.

Answer:

(i) For every action, there is an equal and opposite reaction. The action - reaction forces act on two different objects.
(ii) Newton's third law is obeyed. The stone and the earth exert equal and opposite forces on each other. But the earth's large mass results in negligible acceleration for the same force compared to the stone's acceleration.