Question

# A mass of $10kg$ 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 solution

Open in App
Solution

## Diagram:Explanation:The force is acting downwards in this case.Which is equal to the mass of an object multiplied by the acceleration due to gravity. $F=mg=10×9.81=98.1N$But, according to the question, displacement from A to B is horizontal.Then the angle made between force and displacement will be exactly $90°$.As force and displacement are making a right angle with each other.Work done is the dot product of force and displacement.Now work done $\left(W\right)$= $FS\mathrm{cos}\theta$, where $F$=Force, $S$=Displacement, Hence $W=F×S×\mathrm{cos}90°=0,$ As $\mathrm{cos}90°=0$, whatever be the values of force and displacement,Thus, the net work done will be equal to zero. or $W=0$.Therefore, the work done on the body by gravity is zero.

Suggest Corrections
56