Chapter 10

NCERT
Class 9
Science
Solutions
11. What is the work done by the force of gravity on a satellite moving round the earth? Justify your answer.
Promo GIF

Question:

What is the work done by the force of gravity on a satellite moving round the earth? Justify your answer.

Answer:

The amount of work done on a satellite revolving around the earth is zero when the satellite moves in its circular orbit. In such a situation, the centripetal force acts along the radius of the orbit towards the center and the direction of motion of the satellite is perpendicular to the orbit. Thus the direction of force and displacement are perpendicular to each other.

Therefore work = F × s × cos q = F scos 90° = 0

Hence, work done in case of uniform circular motion is zero.

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