Question

When is work said to be done against the force of gravity? State and define si unit of work.

Answer 1

We know that the gravity acts in the downward direction and if any object is taken upwards from the surface of the earth against gravity then the work is said to be done against the force of gravity. In this case the work done is equal to the product of weight of the body and the vertical distance through which the body is lifted i.e W=mgh

Unit:

The SI unit of work is joule.

1Joule:

When a force of 1 newton moves a body through a distance of 1 m in its own direction,then the work done is 1 joule.