The escape velocity of an object on a planet whose radius is 4 times that of the earth and value of g is same as that on the earth , in `km-s^-1` is

Options

A. 33.6
B. 22.4
C. 16.8
D. 25.2

Answer

B

Explanation

Escape velocity of an object
V_e = `sqrt (2gR_e)`
= `sqrt(2g(4R_e)) (therefore R= 4R_e)`
= 2`sqrt(2gR_e)`
= `2V_e ( "for carth "V_e = 1.2kms^-1)`
`2xx11.2`
`therefore V_e = 22.4kms^-1`