Solve the following examples.

Ravi applied a force of 10 N and moved a book 30 cm in the direction of the force. How much was the work done by Ravi?

Here a book is displaced by 30 cm due to 10 N force, as depicted in the figure

we know work done on an object due to a force is given by relation

W = FS

Where W is the work done due to force F in displacing object by S in the direction of force.

Here the force applied is

F = 10 N

The displacement of book in the direction of force

S = 30 cm

All units should be in SI so converting cm to m

1 cm = 1/100 m

So we get displacement as

S = 30 × 1/100 = 30/100 m = 0.3 m

So work done on the book is

W = 10 N × 0.3 m = 3 N

i.e. Ravi did 3 J work to move the book