Question

4. Water falls from a height of 60 m at the rate of 15 kg/s to
operate a turbine. The losses due to frictional forces are 10%
of energy. How much power is generated by the turbine
(g = 10 ms? )
(a) 12.3 kW (b) 7 kW (C) 8.1 kW (d) 10.2 kW


this is the question​

Answer 1

Explanation:

$loss \: due \: to \: fictionforceis \: 10\% \: \\ therefore \\ \: only \: 90\% \: of \: energy \: is \: used\\ \\ p = gh \frac{m}{t} \times \frac{90}{100} \\ = 8.1kw$

Answer 2

Solution  :

As per the given data,

• Height = 60 m
• Rate = 15 kg / s
• Loss in energy due to frictional forces = 10%

The remaining amt of energy is used to operate the turbine = 90 %

Work done will be in the form of potential energy

Hence,

• W = mgh

here,

• m = mass

• g= acceleration due to gravity

• h = height

And

• P = W/ t

here,

• P = power

• W = work
• t = time

⇒ P = mx g x h / t

On rearranging,

⇒ P = m / t x g x h

⇒ P = 15 x 10 x 60

⇒ P = 8000 W

The power generated by the turbine is 8000 W.