The kinetic energy needed to project a body of mass m from the Earth surface (radius R) to infinity is:

Options

A. `(mgR)/(2)`
B. `2mgR`
C. `mgR`
D. `(mgR)/(4)`

Answer

C

Explanation

`K.E=(1)/(2)mv_(e)^(2)`
where `v_(e)` = escape velocity = `sqrt(2gR)`
`thereforeK.E=(1)/(2)mxx2gR=mgR`