A generator at Hoover Dam can supply 388 MW of electrical power. Assume that the

Question

A generator at Hoover Dam can supply 388 MW of electrical power. Assume that the turbine and the generator are 83% efficient-therefore falling water must supply energy at a rate of 467.5 MW. The acceleration due to gravity is 9.8 m/s^2 .

A) The energy of the water comes from the change of the potential energy (mgh). What is the needed change in potential energy each second?

B) If the water falls 24.9 m, what is the mass of the water that must pass through the turbine each second to supply this power? Answer in units of kg/s.

(Please provide work!)

Explanation / Answer

RawPower = 467.5 MW

1) PE per second = Raw Power = 467.4 MW = 467.5 x 10^6 J/s

3) m g h = PE (this is an equation for 'per second')
m = PE / g h = 467.5 x 10^6/9.8/24.9 = 1.91 x 10^6 kg/s

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.