(i) Work done is given by the product of force and the distance moved by the body.
The work done will be positive when the displacement of the body is in the direction of the
applied force.
For example: A man does work by taking his bag from the ground to his shoulder.
He raises up the bag against the gravity.
Thus, the force exerted and the displacement by the object is in the same direction.
(ii) The work done will be negative when the displacement of the body is in opposite direction to
the applied force.
For example: When a body moves on a ground, the force of friction acts in the opposite
direction to the motion of the body.
So, the work done by the force of friction will be negative.
Final Answer:
The work done will be positive when the displacement of the body is in the direction of the applied force.
For example: A man taking up his bag to his shoulder.
The work done will be negative when the displacement of the body is in the opposite direction to the applied force.
For example: The work done by the force of friction when an object moves.