The Total solution for NCERT class 6-12
According to the third law of motion when we push on an object, theobject pushes back on us with an equal and opposite force. If the object is amassive truck parked along the roadside, it will probably not move. A studentjustifies this by answering that the two opposite and equal forces cancel eachother. Comment on this logic and explain why the truck does not move.
Since the truck has avery high mass, the static friction between the road and the truck is high. Whenpushing the truck with a small force, the frictional force cancels out theapplied force and the truck does not move. This implies that the two forces areequal in magnitude but opposite in direction (since the person pushing thetruck is not displaced when the truck doesn’t move). Therefore, the student’slogic is correct.