Gravitation Question 104
Question: Assertion: For the planets orbiting around the sun, angular speed, linear speed, K.E. changes with time, but angular momentum remains constant. Reason: No torque is acting on the rotating planet. So its angular momentum is constant.
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: A
Solution:
The torque on a body is given by $ [\overrightarrow{\tau }=\frac{d\overrightarrow{L}}{dt}] $ In case of planet orbiting around sun no torque is acting on it. $ [\frac{d\overrightarrow{L}}{dt}=0] $ Þ $ [\overrightarrow{L}] $ = constant.
