Work is said to be done when a force applied to an object moves that object.
When force and displacement are in the same direction, the work performed on an object is said to be positive work.
Example: When a body moves on the horizontal surface, force and displacement act in the forward path. The work is done in this case known as Positive work.
Negative work is performed if the displacement is opposite to the direction of the Force applied.
Example: Work was done the gravity on a rocket going perpendicular upwards.
When force and displacement are perpendicular to each other, or when force or displacement is zero.
Example: When we hold an object and walk, the force acts in a downward direction whereas displacement acts in the forward direction.