- #1

kriegera

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## Homework Statement

My teacher assigned a horsepower problem except that we never covered horsepower. Here's my attempt:

One of the Niagara turbines uses 172,000 cubic feet of water per minute under a head of 215 ft. What is the horsepower developed?

## Homework Equations

## The Attempt at a Solution

The total horsepower developed by water falling from a given height is the product of the mass flow rate in pounds per minute times the falling height in feet divided by 33,000. It can be expressed as:

Php = mmin h g / 33000

where

Php = power (horsepower, hp)

mmin = mass flow rate per minute (lbm/min)

h = head or height (ft)

g = acceleration of gravity (32 ft/s2)

Convert 172,000 cubic feet of water per minute to pounds per minute: A cubic foot of air is approximately 0.0807 lbs (172,000)(0.0807)=13880.4 lb/minute

Php = (13,880.4)(215)(9.8) / 33000= 8,862.42 hp

-Am I on track here? Also, I used 9.8 for acceleration of gravity-can anyone tell me if this is the value I should be using? Thanks!