A lifting machine, having an efficiency of `80 %` uses `2500 J` of energy in lifting a `10 kg` load over a certain height. If the load is now allowed to fall through that height freely, its velocity at the end of the fall will be `(g =10 m//s^(2))`

Options

A. `10 ms^(-1)`
B. `15 ms^(-1)`
C. `20 m s^(-1)`
D. `25 m s^(-1)`

Answer

C

Explanation

`(80)/(100) xx E = (1)/(2) mv^(2)`.