SI Unit of Work

W = F x s

SI unit of F is N and that of s is m [N=Newton]

1Nm is defined as 1 joule.

i.e., 1 joule = 1Nm

One joule is the work done, when the point of application of a force of one Newton moves through a distance of one meter in the direction of force.

1Nm is referred as joule after the British Scientist James Prescott Joule.

The letter 'J' denotes Joule.

Higher units of work are kilojoule and Megajoule.

Sub Topics

Numericals

01. An object of mass 5 kg is lifted up through a distance of 2 meter. What is the work done?

Solution:

W = F x s

Also, force acting on the object is F = mg [Newton's second law of motion]

Mass of the object (m) = 5 kg

Distance moved = 2m

Therefore, Work done = F x s

02. How much work is done, when a force of 25N displaces an object through 10m, in the direction of the force applied?

Solution:

Distance moved (s) = 10m

Work done (W) = F x s

03. A work of 250J is done when a force of 10N is applied on an object. Calculate the distance through which the object moves.

Solution:Work done (W) = 250 J

Force applied (F) = 10 N

Distance (s) = ?

W = F x s

Distance covered = 25m