State whether the work done in the following cases is positive or negative.
Work done by gravity when a body is thrown up.

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Solution

The body is moving upward, but the gravitational force acts in bringing the body down, towards the surface of the earth.
The displacement is in the opposite direction of the force acting on the body.
$W o r k d o n e = F o r c e \times D i s p l a c e m e n t \times A n g l e b e t w e e n t h e m W = F S \cos θ f o r W = - v e = \cos θ = - 1 = \cos 180$
Hence, the work done by gravity is negative.

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State whether the work done in the following cases is positive or negative.Work done by gravity when a body is thrown up.

State whether the work done in the following cases is positive or negative.
Work done by gravity when a body is thrown up.