An asteroid of mass m is approaching earth, initially at distance of `10R_(e )` with speed `v_i`. It hits the earth with speed vf (Re and `M_e` are radius and mass of the earth then

Options

A. `v_(f)^(2)= v_(i)^(2) +(2Gm)/(M_(e )R) (1-(1)/(10))`
B. `v_(f)^(2)= v_(i)^(2) +(2GM_(e ))/(R_( e)) (1+(1)/(10))`
C. `v_(f)^(2)= v_(i)^(2) +(2GM_e)/(R_e) (1-(1)/(10))`
D. `v_(f)^(2)= v_(i)^(2) +(2G)/(R_e) (1-(1)/(10))`

Answer

C