Question

When a fast-moving vehicle is suddenly stopped by applying the brake, the force that causes deceleration is exerted by the brake.

• A. Due to opposing force of friction
• B. Because action and reaction pair are never equal

Answer 1

The correct option is B

Because action and reaction pair are never equal

The force exerted by brake is an internal force for the car. Internal force can not cause deceleration. The brake's function is just to stop the rotation of the wheels. Once the rotation of the wheels is stopped, the wheels start to slide on the road. The frictional force opposes this sliding and causes deceleration. Hence, the above statement is false.