Answer to Question #248431 in Physics for Lorenz

Question

Why should we always neglect effects of friction and/or air resistance in uniform motion?

Answer 1

Because uniform motion implies that all forces acting on the body are balanced, or that the net force is zero. If we consider an object that moves by inertia with the drag or frictional force, the net force is not zero and the motion will be decelerated (non-uniform), and we will have to introduce new forces to make it uniform, which is absurd.

That is why we neglect the mentioned forces.