# electrical force in terms of mechanical force?

Discussion in 'General Electronics Chat' started by Mathematics!, Feb 14, 2010.

1. ### Mathematics! Thread Starter Senior Member

Jul 21, 2008
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Ok , what I am trying to figure out is given the amount of watts or voltage and current... someway to determine the equivalant mechanical force...

For example say I can lift 300lbs = 1334.46 Newtons

What is the electrical equivalent lifting this much weight one foot?

So I guess what I am saying is what is the electrical equivalent of
300ft-lbs?

I know work is measured in energy which is joules = 1N*m = 1W*s
But I don't know what 1Watt -second looks like (no frame of reference)

Like for a 60watt light bulb is it being supplied with 60watts each second or more or less....

In terms of RMS the ac is the equivalent steady dc so I would think 60watt bulb gets supplied 60watts a second which means 60watt-seconds =60 joules and from their convert it into foot-lbs

=> 44.253 ft-lbs which means powering a light bulb for one second is the equivalent of lifting 44.253 lbs one foot.

Correct me if I am wrong
Does seem a bit much just to power a light bulb for a second????

Thanks for any help or clarity with this question

2. ### retched AAC Fanatic!

Dec 5, 2009
5,201
313
Code ( (Unknown Language)):
1. 1 watt = 1 volt X 1 ampere
2. 1 watt = 3.41 BTU
3. 746 watts = 1 horsepower
4.
5. A horsepower is a unit of power equal to 746 watts or 33,000 lb.ft per minute (or 550 lb.ft per second).
60 watt bulb is .08 Horsepower.
.08 HP is ~44lbs/ft/sec

It does infact seem like a lot of power. If you compare it to the same light output from 60w equivalent LEDs is ~7w.

Last edited: Feb 15, 2010
3. ### Mathematics! Thread Starter Senior Member

Jul 21, 2008
1,022
4
So that means I was correct in saying a 60watt bulb powered on for one second is the equivalent of lifting 44lbs one foot or 22lbs two feet ,...etc

That seems like a lot of work if some one was to mechanically lift 44lbs most would tire out around the 12 rep... so if you where doing a rep a second then you would only beable to power a 60 watt light bulb for 12 seconds.....diffcult just for light

Thanks
I did all my calculations interms of work/energy you are doing them interms of power which gives equivalent results
1J = 1W*s = 1N *m =...etc
W = F * d
E = P * t ,...etc

Last edited: Feb 15, 2010
4. ### Papabravo Expert

Feb 24, 2006
10,340
1,850
There is an instuctive display at the Ann Arbor Hands On Museum that has a geared mechanical crank driving an AC generator with 3 switched 60 watt light bulbs in parallel as loads. With no load the average person can easily turn the crank and create an open circuit voltage of 120VAC. Switch in that first 60 watt bulb and it becomes more difficult, but not impossible to keep that first bulb lit. Switch in the second bulb and it becomes way more difficult. The third one brings the whole process naerly to a stop.

5. ### Mathematics! Thread Starter Senior Member

Jul 21, 2008
1,022
4
Cool,

How many tesla's do you need a magnet to be to pick up 300lbs a foot?

And if you where going to make a electromagnet using a coil of wire how many coils would you need /how tight ..etc to get the equivalent magnet in tesla's using a 120vac house outlet as the power supply????

Thanks

6. ### KL7AJ AAC Fanatic!

Nov 4, 2008
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295
Waaaay back in one of my vacuum tube archives there's a chart that shows electron acceleration as a function of plate voltage and spacing. I'm sure a good physics reference has that as well.

eric

7. ### Papabravo Expert

Feb 24, 2006
10,340
1,850
The following wikipedia article has the information you seek under the heading: "Force exerted by a magnetic field"

http://en.wikipedia.org/wiki/Electromagnet

It also says that an exploding electromagent can produce 1000T for a few microseconds. I'd like to see that, but only a government scientist could contemplate that experiment.