Question

Moon revolve around the earth,the gravitational force is exerted by the earth on moon this gravitational force do negative work, positive work or no work?

Answer 1

Answer:

When the moon revolves around the earth, a gravitational force is exerted by the earth on the moon. This gravitational force does no work.

Explanation:

When the moon revolves around the earth it follows a nearly circular path. The necessary force to perform this motion is given by the centripetal force.

We know, Work done, W = F × ds Cosθ

Where F is the centripetal force, ds is the displacement made by the moon and θ is the angle between the force vector and displacement.

This centripetal force will always be in a direction perpendicular to the displacement of the moon since it follows a circular path.

∴ θ = 90°

 W = F × ds Cos90

  W = F × ds × 0                    [∵ Cos90]

∴ W = 0