Suppose that the earth revolves around the sun in a perfectly circular orbit. Does the sun do any work on the earth?

Suppose that the earth revolves around the sun in a perfectly circular

1.	Suppose that the earth revolves around the sun in a perfectly circular orbit. Does the sun do any work on the earth?
Answer» Solution :When the earth revolves around the sun in a perfectly circular orbit the force of the sun on the earth is along the RADIUS while displacement of the earth is along the TANGENT to the orbit. Now in a circle, radius and tangent are always orthogonal i.e., ANGLE between them at any point on the orbit is `90^(@)` and so,work done by the sun on the earth is ZERO.