Thread: how to compute work

hello all and thank you for reading this. any and all help will be greatly appreciated. i am trying figure out if air pressure can be converted to horsepower.

i know what 1 horsepower is equal to in the sense of work performed. although horsepower does seem to be a rather vague way of describing work. what has me backwards is if the energy created by air pressure can be coverted over to horsepower.

so if x amount of air pressure pushes down on a y size piston how much energy can be transfered through the piston?

if none of this makes sense let e know and i'll try to explain better. it seems easy to think about but for some reason just has me all confused when i try to solve it.

thank you

Originally Posted by jmurphy

hello all and thank you for reading this. any and all help will be greatly appreciated. i am trying figure out if air pressure can be converted to horsepower.

i know what 1 horsepower is equal to in the sense of work performed. although horsepower does seem to be a rather vague way of describing work. what has me backwards is if the energy created by air pressure can be coverted over to horsepower.

Horsepower is a rate of doing work, not work itself.

so if x amount of air pressure pushes down on a y size piston how much energy can be transfered through the piston?

It depends on the pressure on the otherside of the piston. In a rational set
of units the work done is the nett force times the distance moved by the point of
application.

Unfortunatly horse power is not part of a rational set of units and you will
have to work in Watts, metres and Newtons which are the relevant SI units
if you want to make this simple.

Watts are Joules per second which are Newton metres per second, and a
Newton is a kg metre per second per second.

RonL

thank you for the input. a piston was a poor example on my part, i apologize.

if your familiar with a wabkel design of engine using a rotor that spins rather, than pistons, a negative pressure or slight vaccuum could be created on the back side of the mass being moved requiring less energy to move the rotor.
so if we stayed somewhat simple and used a 1 square inch surface area with 100 lbs of pressure on a rotating mass of say 10 lbs is there a g-wiz great math formula to solve the amount of being done.

i know many things do come into play, friction loss for example. i may be looking for a mathmatical answer to a physical problem, if so thats the breaks. nice catch on the horsepower, is is a horrible way to figure work being done but its my first math question in a long time. should have considered who would be giving me answers.

i kind of think of it like a pinwheel. considering the mass the wheel and its resistance to move can i use mathe to find how much aie pressure is required to move the wheel?