Question

according to the third law of motion when we push on an object the object pushes back on us with an equal and opposite force. If the object is a massive truck parked along the roadside

Answer 1

The justification given by the student that two opposite and equal forces cancel each other and hence truck does not move is wrong.

This is because the forces of action and reaction do not act on the same body.

So, there is no question for their cancellation. Actually, the massive truck does not move in this case because push applied to it is much smaller than the force of friction between the wheels on the truck and the road.

Since the force of push is not able to overcome the force of friction, therefore, the truck does not move.