Re: 777 rejected takeoff test

Date:         01 Nov 97 18:55:53 
From:         drela@mit.edu (Mark Drela)
Organization: Massachvsetts Institvte of Technology
References:   1 2 3
Followups:    1
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In article <airliners.1997.2470@ohare.Chicago.COM>, Syiad.Al-Duri@t-online.de (Syiad T. Al-Duri) writes:
> Stephen H. Westin wrote in sci.aeronautics.airliners:
> > wb8foz@netcom.com (David Lesher) writes:
> >> Err... I was always an SI type, but is that a viable unit for the
> >> test? I was looking for energy, not torque.
>
> > Absolutely. Pounds-feet is torque; foot-pounds is energy.
>
> > Energy is equivalent to work: a given force exerted over a given
> > distance. Hence foot-pounds.
>
> There's no difference between Torque and Energy. That's why they have the
> same dimension, force multiplied by distance.

Units alone to not constitute a physical concept.
Energy is a dot product and Torque is a cross product.
They are not the same thing.

I would even argue that they have different units conceptually,
since Torque has the units of Energy/radian, not just Energy.

  Mark Drela                          First Law of Aviation:
  MIT Aero & Astro          "Takeoff is optional, landing is compulsory"