Here's why:
* Uniform speed means the object is not accelerating.
* Newton's First Law of Motion states that an object at rest stays at rest, and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
* Perfectly smooth road means there is no friction between the body and the road. Friction is a force that opposes motion.
Since there is no acceleration and no friction, there is no net force acting on the body.
However, there might be forces present that are balanced:
* Gravity: Acts downwards on the body, but it is balanced by the normal force from the road.
* Air resistance: While a perfectly smooth road eliminates friction, there will still be some air resistance if the body is moving through air. This force would be extremely small in a perfect scenario, but it's worth noting.
In essence, the body is moving in a state of equilibrium where all forces are balanced.
