Hi, I think this is my first post here, be gentle please I have a question I posted on StackExchange (I forgot about here) and got one answer, but it, the answer is beyond me. Basically, I have a rod that pushes up a travel of 5mm, with a force* between 9.5 and 2kg. It does this in 0.02 seconds. I calculate I can get about 10 watts of electrical power from this - am I in the correct ballpark?

* re force, I know it's measured in Newtons. I simply multiple by 9.8, correct?

I reproduce the question I posted below.

Thanks, Kevin!

I am trying to estimate the electrical power a mechanical machine may generate - is my calculations/understanding correct (to a plus/minus 50% error)?

So, I have a mechanical machine whereby a shaft is pushed up (by what I'd rather not say) and is returned at the top of the stroke by a spring, then the process repeats. Similar to a piston in an ICE.

The 'force' (I'll explain shortly) is not linear along it's travel. It goes from 9.5Kg at 1mm from start, to 2Kg at 6mm. Averaging all my data points I get 4.3Kg over a distance of 5mm.

I understand force is measured in Newtons, so I can just multiple by 9.8?

This process repeats 50 times a second, or every 0.02 seconds.

So, if I connect this to a crankshaft and turn a generator, I believe I will get 10.5 watts of electrical power, assuming no losses, and using my method of simply averaging the force along the travel,

I get 10.5W like so:

Power in watts = work in joules / time

Power in watts = 4.3Kg * 0.005 meters * 9.8 / 0.02 seconds

**Edit in response to Mike Jordan's answer.**

Unfortunately, I do not understand your answer. This is not my area so am just trying to get a proof of concept before getting the assistance I clearly need.

To try to answer your questions at the end, yes, I'm measuring the force with a load cell calibrated in Kgs.

*Since you have the spatial average not the temporal one (right?)* - I don't know, I guess the former? Are you saying to multiply the stroke (5mm) by what value? Is that what I did? Is my answer then per stroke?