Question

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

Answer 1

zero work is said to be done if the force applied on the body doesn't displace the body.
when u apply brakes and when and you are pushing something but the object is still coming to u

Answer 2

work done can be zero in three cases
a) if F is 0
b) is displacement is 0
c) if force and displacement are at 90° angle
negative work is due to angle and not due to direction so work is a scalar quantity
negative work done is when angle between force and displacement is 0
for e. g take case of a body thrown up work done by gravity is negative
or take friction as e. g