Question

Question 5
A mass of 10 kg is at a point A on a table. It is moved to a point B. If the line joining A and B is horizontal, what is the work done on the object by the gravitational force? Explain your answer.

Answer 1

Work is said to be done when force acting on the body displaces it.
Work done by gravity depends only on the vertical displacement of the body. It does not depend upon the path of the body. Therefore, work done by gravity is given by the expression,
$W=mgh$
where, vertical displacement, $h=0$
$\therefore W=mg\times 0=0$
Hence, the work done by gravity on the body is zero.