Science Made Easy
Types of work
(i) Zero work: If the angle between force and displacement is 90°, then work done is said to be zero work.
Example: When a man carries a load on his hand and moves on a level road, work done by the man on the load is zero.
(ii) Positive work: Work done is said to be positive if force applied on an object and displacement are in the same direction.
Example: Work done by the force of gravity on a falling body is positive.
(iii) Negative work: Work done is said to be negative if the applied force on an object and displacement are in opposite direction.
W = -Fs
Here displacement is taken to be negative (-s).
Example: Work done by friction force is usually negative on a moving body.
