Answer:
The efficiency of the windmill is 37.52 %.
Explanation:
Given that,
A gust of wind does 125 J of work on the blades of a windmill, [tex]W_i=125\ J[/tex]
The windmill can do 46.9 J of useful work output, [tex]W_o=46.9\ J[/tex]
We need to find the efficiency of the windmill. It is given by the ratio of output work to the input work. So,
[tex]\eta=\dfrac{W_o}{W_i}\times 100\\\\\eta=\dfrac{46.9}{125}\times 100\\\\\eta=37.52\%[/tex]
So, the efficiency of the windmill is 37.52 %.