Question

23. A student lifts an object in the upward direction. In doing so he applies the force on the
obiect in the upward direction and displaced it in that direction
State the direction in which force of gravity is acting on it
in) Name the forces which in doing positive work and negative work
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Answer 1

Here's ur answer

a) The direction in which the force of gravity works is downward direction.

b) The force of gravity is doing positive work, because, the force pulls down and the value of theta is 0 . So, cos theta=cos 0 degree=1. Thus, work done by force of gravity is positive.

c) The student does a negative work, because, the angle between lifting the body and force of gravity is 180 degree. Thus, cos theta=cos 180 degree= -1.

Hence, the work done by the boy is negative.

Hope it helps.....;););)

Answer 2

FORCE OF GRAVITY IS ACTING IN DOWNWARD DIRECTION..

STUDENT IS DOING POSITIVE WORK BCOZ THE DIRECTION OF FORCE APPLIED AND DISPLACEMENT R SAME

GRAVITATIONAL FORCE IS DOING NEGATIVE WORK BCOZ THE DIRECTION OF FORCE APPLIED AND DISPLACEMENT IS OPPOSITE.....!!!!