Register to reply

Calculating e=mc^2 using foot-pounds of force

by markteller
Tags: foot pounds, force, speed of light
Share this thread:
markteller
#1
Jun29-13, 07:08 PM
P: 2
I have seen the on-line calculators, but would like to see how the formula works in full detail. I have seen the kilograms / meters / second example already.

The second part of the question is, what is the actual formula for converting foot pounds of force to Newton meters? Again, the actual details.

Thanks...
Phys.Org News Partner Physics news on Phys.org
A new, tunable device for spintronics
Watching the structure of glass under pressure
New imaging technique shows how cocaine shuts down blood flow in mouse brains
DrewD
#2
Jun29-13, 08:07 PM
P: 446
Quote Quote by markteller View Post
I have seen the on-line calculators, but would like to see how the formula works in full detail. I have seen the kilograms / meters / second example already.

The second part of the question is, what is the actual formula for converting foot pounds of force to Newton meters? Again, the actual details.

Thanks...
What sort of details are you looking for? For the first part, if you just want to calculate the rest energy, then you plug in ##m## and ##c## and get a number. Deriving the formula requires a bit more effort and can be found easily online. If you choose to meters, kilograms, seconds, then you get the energy in Joules. If you want it in ft*lbs then you use the conversion factor. According to the all powerful google, it is ##1\ J=0.7375ft\cdot lbs##.

If you wanted to, you could multiply the individual conversion factors to get there. That is, the conversion meters to feet and Newtons to lbs (of force) and get the same number.

Is this what you are asking about or did I misunderstand your question.
markteller
#3
Jun30-13, 11:30 AM
P: 2
Thanks!

I am looking to convert 1 kilogram of mass into foot-pounds using e=mc^2 and without any unnecessary conversions. I want to see how the final number is arrived at.

I then want to see how foot-pounds are converted back to newton meters, which are more typical for e=mc^2. Again, I know there are online calculators, but they don't educate the mind :)

jtbell
#4
Jun30-13, 02:24 PM
Mentor
jtbell's Avatar
P: 11,778
Calculating e=mc^2 using foot-pounds of force

In the spirit of teaching a man how to fish versus simply giving him a fish, it looks like you might benefit from a tutorial on "how to convert units". Here's the first one I found with a Google search on that phrase:

http://oakroadsystems.com/math/convert.htm

Then try to do the conversion yourself, show us the details and the result, and we can give you hints for correcting it if necessary.


Register to reply

Related Discussions
Force exerted: on a foot run over by a car VS a car staying on a foot for longer General Physics 4
Calculating pressure given dia. and pounds Introductory Physics Homework 2
Calculating speed of light in substance Introductory Physics Homework 1
What is the formula for calculating the speed of thought? Biology 6
Calculating earth's speed using radius and speed of light, etc. Introductory Physics Homework 8