What do you mean by zero work, positive work and negative work?
Positive work:
When the force acting on the body and its displacement are in same direction, positive work is done.
Eg: You are pushing a box and the box moves in the direction you are pushing it in.
Work done W = F* s where F is the force applied and s is the displacement.
Negative work:
When the force acting on the body and its displacement are in opposite direction, negative work is done.
Eg: When a body is lifted, the work done by gravitational force is negative.
Zero work:
When the force is acting on the body but its displacement is 0, work done is 0.
Eg: When we push hard against a wall, the force we exert on the wall does no work, because s = 0. However, in this process, our muscles are contracting and relaxing alternately and internal energy is used. That is why we get tired.
Positive work:
When the force acting on the body and its displacement are in same direction, positive work is done.
Eg: You are pushing a box and the box moves in the direction you are pushing it in.
Work done W = F* s where F is the force applied and s is the displacement.
Negative work:
When the force acting on the body and its displacement are in opposite direction, negative work is done.
Eg: When a body is lifted, the work done by gravitational force is negative.
Zero work:
When the force is acting on the body but its displacement is 0, work done is 0.
Eg: When we push hard against a wall, the force we exert on the wall does no work, because s = 0. However, in this process, our muscles are contracting and relaxing alternately and internal energy is used. That is why we get tired.
