Explanation:
a. " for every action there is an equal and opposite reaction".
b. The electric fan does not stop moving just after the switch turns off because of rational inertia force.
c. The force applied to first vehicle is 120N.
d. In my view it doesn't support the law of conservation of momentum. Momentum of 1 and 2 object before the collision is equal to the total momentum of two object after collision.
