Q. Suppose an earth satellite, revolving in a circular orbit, experiences a resistance due to cosmic dust. Then :

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Its kinetic energy will increase

Its potential energy will decrease

It will spiral towards the earth and in the process its angular momentum will remain conserved

It will get heated and burn off ultimately or fall somewhere on the surface of earth

Solution:

Due to dust it experiences an opposition force due to which its speed will decrease and due to which it is attracted toward the earth by gravitational force and in this process gravitational force will do work on satellite and its kinetic energy will increase continuously more than the opposition work done and as it gets closer to earth center its potential energy will decrease. It will move in spiral path but due to torque of opposition force angular momentum will not be conserved. Due to dust friction it gets heated and may burn off before falling on earth surface.

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