What term is used for the forces that are responsible for slowing down the body?

The term that accurately describes the forces responsible for slowing down the body is "deceleration force." Deceleration refers specifically to a decrease in speed or a change in velocity in the opposite direction. When an object or body is experiencing deceleration, it is being slowed down due to various forces at play, which can include friction, air resistance, and other resistive forces.

The context of deceleration is crucial in understanding mechanics. A braking force is specifically associated with stopping or reducing the speed of a vehicle or object rather than describing the broader concept of deceleration itself. While friction force and resistance force can contribute to slowing down, they do not encompass all scenarios of deceleration. Therefore, deceleration force is the most precise term for the forces that actively reduce the motion of a body.