A body is projected with a velocity of `2 xx 11.2 kms^(-1)` from the surface of earth. The velocity of the body when it escapes the gravitational pull of earth is

Options

A. `sqrt(3) xx 11.2 kms^(-1)`
B. 11.2 `kms^(-1)`
C. `sqrt(2) xx 11.2 kms^(-1)`
D. `6.5 xx 11.2 kms^(-1)`

Answer

B

Explanation

`KE = (1)/(2)mv^(2)-(1)/(2)m(11.2)^(2)`
`= (1)/(2)m(2 xx 11.2)^(2) - (1)/(2)m(11.2)^(2)`
`(1)/(2) mv^(2) = 3 xx (1)/(2) m xx (11.2)^(2)`
`v = sqrt(3) xx 11.2`