Gravitation Question 153
Question: Given mass of the moon is 1/81 of the mass of the earth and corresponding radius is 1/4 of the earth. If escape velocity on the earth surface is11.2 km/s, the value of same on the surface of the moon is [CPMT 1997; AIIMS 2000; Pb. PMT 2001]
Options:
A) 0.14 km/s
B) 0.5 km/s
C) 2.5 km/s
D) 5 km/s
Show Answer
Answer:
Correct Answer: C
Solution:
On earth $ [v _{e}=\sqrt{\frac{2GM}{R}}=11.2,,km/s] $
On moon $ [v _{m}=\sqrt{\frac{2GM\times 4}{81\times R}}=\frac{2}{9},\sqrt{\frac{2GM}{R}}] $ $ [=\frac{2}{9}\times 11.2=2.5,,km/s] $
