Question

Define negative work . Give two examples where negative work is done?

Answer 1

work done is negative when 90o < θ <= 180o as Cos θ is negative. We can also say that work done by a force is negative if the applied force has a component in a direction opposite to the displacement.

examples:- work done by frictional force
                     work done by gravitational force

Answer 2

work done is against the direction of force applied then negative work is done.
Ex- Work done by frictional force
Work done by gravitational force