What is cos (theta) in the formula of work done ? Please explain with example?

Dear student

Cos theta in the definition of work done is cos of the angle between force applied and the displacement.

For example, for a body freely falling under the effect of gravity,

F = mg

The direction of displacement & force is same, hence the angle between the two vectors is zero. So work done by gravitational force on freely falling body is W = mghcos0

 

For a ball thrown up against the gravity,

the force is acting downwards & the displacement is upwards.

So the angle between F and Displacement is 180

So work done by gravity on a ball moving up is W = mgh cos180

 

 

Regards

Team

TopperLearning