A machine rated as `150 W`, changes the velocity of a `10 kg` mass from `4 ms^(-1)` to `10 ms^(-1)` in `4s`. The efficiency of the machine is nearly.

Options

A. `70%`
B. `30%`
C. `50%`
D. `40%`

Answer

A

Explanation

`eta = (P_(0))/(P_(i)) xx 1000` where `p_(0) = ((1)/(2),[v^(2)-u^(2)])/(t)`.