Gravitation Question 88
Question: Assertion: If an earth satellite moves to a lower orbit, there is some dissipation of energy but the satellite speed increases. Reason: The speed of satellite is a constant quantity.
Options:
A) If both assertion and reason are true and the reason is the correct explanation of the assertion.
B) If both assertion and reason are true but reason is not the correct explanation of the assertion.
C) If assertion is true but reason is false.
D) If the assertion and reason both are false.
E) If assertion is false but reason is true.
Show Answer
Answer:
Correct Answer: C
Solution:
Due to resistance force of atmosphere, the satellite revolving around the earth losses kinetic energy. Therefore in a particular orbit the gravitational attraction of earth on satellite becomes greater than that required for circular orbit there. Therefore satellite moves down to a lower orbit. In the lower orbit as the potential energy$ [(U=-GMm/r)] $ becomes more negative, Hence kinetic energy $ [\left( E_{K}=GMm/2r \right)] $ increases, and hence speed of satellite increases.
