Question

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​

Answer 1

Answer:

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.

Answer 2

Answer:

$\huge{\tt{\red{}\green{A}\purple{N}\pink{S}\blue{W}\orange{E}\red{R}}}♤♤$

Mass of water falling/second = 15 kg/s h = 60 m, g = 10 m/s2, loss = 10 % i.e., 90% is used. Power generated = 15 x 10 x 60 x 0.9 = 8100 W = 8.1 kW.