Question

A boy is carrying a suitcase of $3kg$ mass on his back and moves $200m$ on a leveled road. If the value of $g$ be $10m/s^2$ , the work done by the boy against the gravitational force will be:

• A. $6000J$
• B. $0J$
• C. $120J$
• D. $800J$

Answer 1

Answer: (B)

$0J$

Work done against gravitational force $W=mgh$

where $h$ is the vertical displacement of the suitcase.

As the boy carries the suitcase on his back and moves on a leveled road, thus displacement of the boy (or the suitcase) in the vertical direction is zero i.e. $h=0$

$⟹$ $W=0J$