Q. 394.6( 12 Votes )
When is the work done by a force on a body?
(b) Negative, and
(a) Work done is positive, when a force acts in the direction of motion of the body.
For e.g. kicking a football
(b) Work done is negative, when a force acts opposite to the direction of motion of the body
For e.g. when a body is being lifted in the upward direction
(c) Work done is zero when a force acts at right angles to the direction of motion of the body
For e.g. No work is done by the porter in carrying the load.
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