Question

An object of mass m Kg is raised to a height h from the earth surface. Calculate. i) Work done by the force of gravity. ii) Work done by the external force. iii) Potential energy stored in the object. ​

Answer 1

Answer:

the work done by the object

Answer 2

Given:

An object of mass m Kg is raised to a height h from the earth surface

To Find:

i) Work done by the force of gravity.

ii) Work done by the external force.

iii) Potential energy stored in the object. ​

Solution:

The work done by a force is the scalar product of the force producing the work and the displacement of the object.

Mathematically,

W = F.s cos∅

Here ∅ is the angle between the force and the displacement

i) Applying the above formula, the work done by the force of gravity

= (mg) . h . cos 180

= -mgh

ii) The work done by the external force

= (mg) . h . cos 0

= mgh

iii) The work done to lift an object is equal to the potential energy that gets stored in the object.

Hence, the potential energy stored in the object = mgh