The mass of the earth is 81 times that of the moon and the radius of the earth is 3.5 times that of the moon. The ratio of the escape velocity on the surface of earth to that on the surface of moon will be

Options

A. 0.2
B. 2.57
C. 4.81
D. 0.39

Answer

C

Explanation

Escape velocity, `v_(e)=sqrt((2GM)/(R))`
`therefore (v_(e))/(v_(m))sqrt((M_(e)R_(m))/(M_(m)R_(e)))`
`(v_(e))/(v_(m))=sqrt((81)/(3.5))=4.81`