What is the work done by a constant force ? When is it positive, negative or zero ?

Explain work done by a constant force .

When is the work done by a force zero?

For a man walking on the floor, the force of friction between the floor and his feet accelerates him forword. What will be work done by the force of friction, postive, negative or zero?

Is the work done by a frictional froce be positive or negative ?

When is the work done by gravity negative ?

work done by constant force and variable force

when is the work done by a force negative.

When is the work done by a force is positive and when is it negative ?