What is the escape velocity for body on the surface of planet on which the accelearation due to gravity is `(3.1)^(2)ms^(2)` and whose radius is 8100 km ?

Options

A. `2790 kms^(-1)`
B. `27.9 kms^(-1)`
C. `27.9 sqrt(5) kms^(-1)`
D. `2.79 sqrt(5) kms^(-1)`

Answer

C

Explanation

Escape velocity `V_(e )=sqrt(2gR)`
Given `v_(e )=sqrt(2xx(3.1)^(2)xx8100xx10^(3))=12.5xx10^(3) ms^(-1)`
`rarr v_(e)=12.5 kms^(-1)=(27.9)/sqrt(5)kms^(-1)`