Can work be negative positive or zero?

Asked by Vasudha Balaji | 22nd Oct, 2013, 07:19: PM

Expert Answer:

Work done is positive if there is positive displacement is in direction of applied force.

For e.g.

(1) pushing a cart and it moves forward.

(2) Lifting a bucket of water

(3) Climbing a tree

(4) Kicking a football

Work done is negative when there is negative displacement in direction of applied force.

i.e. the work done by frictional force against a moving body.

For e.g.

(1) The work done by the frictional force, when we push the book to a distance.

(2) The work done by the frictional force of air, when a ball is falling downwards.

Work done is zero if there is no unbalanced force applied or if there is no displacement in the direction of applied force.

For e.g,

(1) When you try to move a large rock but fails, then the work done will be zero.

(2) If we push a wall, the wall remains unaltered. The work done by us on the wall is zero.

(3) If we try to move a heavy box, and the box is not at all moving, then the work done by us will be zero.

Answered by Faiza Lambe | 23rd Oct, 2013, 07:43: AM

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