Question

How much work is done when a body moves with uniform velocity?

Answer 1

It depends -- see below.

Explanation:

• If it is moving horizontally without friction (or other opposition like air drag), zero work because uniform velocity requires zero net force.
• If it is moving horizontally with friction (or other opposition), then (because of the uniform velocity) we know that the force of friction has been matched by some outside force (equal and opposite). The outside force does work given by `W = F_"outside"*"distance"`
• If it is moving vertically up, it requires work equal to the gain in gravitational potential energy. And additional work if there is friction.

I hope this helps,
Steve