Water falls from a height of 60 m at the rate of 15 kg/s to operate a turbine.  The losses due to frictional force are 10% of the input energy.  How much power is generated by the turbine? (g = 10 m/ $s^2$) 

Given, h = 60m

Now, water falls at the rate of 15 kg is

i.e.,   $\frac{m}{t}=15kg/s$

g = 10 m/$s^2$ 

As loss due to friction is 10%, therefore only 90% of input energy is used to generate power.

$\therefore$ $\frac{m}{t}\times \frac{90}{100}$

P = 10 x 60 x 15 x $\frac{90}{100}$=8100 W $\Rightarrow$P=8.1kW