Re: Deadlift Harder Than Bench Press??


"Andrzej Rosa" <bakters@xxxxxxxxx> wrote in message
news:fdek75$pdf$2@xxxxxxxxxxxxxxxxxx
Dnia Wed, 26 Sep 2007 o 23:31 GMT Hobbes napisa³(a):
[...]
I'm not so sure. It's crossposted to sci.physics...

Oops. Didn't notice the cross-post or I might have been a little more
rigorous in my formula. Which is actually tough because I've never
expressed a square in a formula in usenet. But if you did break it down
into kinetic energy you could explain the help the bench shirt does as
well.

Now I got it.

--
Andrzej Rosa 1127R

Unfortunately Tom Morley is no longer here. I don't think calculating force
or kinetic energy would be a trivial matter, since both would be constantly
changing over the course of the lift, and somewhat dependent on the
individual lifter. At the top of the lift the KE would be zero, but
potential energy would be highest. The potential energy would not correspond
to the highest momentum achieved, since the bar is accelerated over time.
The bar could be lifted to the same eventual height at different velocities.
Additionally , force could be applied in an extremely short burst or over a
longer interval. If the question relates to the maximal force applied to the
bar, the position of the bar against time would need to be plotted. From
these points you could calculate velocity and acceleration, from
instantaneous acceleration times the mass you would get the force. The
typical elementary physics problems assume an initial velocity, hence, an
initial momentum and the constant force of gravity. From there you can
calculate position, velocity against time using simple calculus. In the
lifting example, we have a changing force applied over time.


.

Relevant Pages

  • Re: Strange paradox.
    ... represents a parabolic increase in velocity rather than a linear ... and is more akin to acceleration of the ... A 1500 kg car accelerates at a constant rate from 0 to 20 m/s and then ... The increase in kinetic energy in the second 10 s is (40^2 - ...
    (sci.physics)
  • Re: Mass was Re: Questions (Space)
    ... T+epsilon the velocity in the X direction is equal to V minus some small ... This "acceleration" in Y, is that your source of added kinetic energy? ... That is also something which is featured in every textbook I ...
    (rec.arts.sf.composition)
  • Re: Hydraulic Presses and Force
    ... acceleration because force can also be defined as "that which causes ... mass balanced in a scale udergoes no change of momentum, ... kinetic energy so as to highlight the relationship of kinetic energy ... acclerated the mass to the constant velocity. ...
    (sci.physics)
  • Re: Mass was Re: Questions (Space)
    ... energy", ... Nothing can change the magnitude /or/ direction of its velocity vector ... without acceleration; that's the difference between Special and General ... It is not having kinetic energy added to it, ...
    (rec.arts.sf.composition)
  • Re: A challenge to non-SRians
    ... Except if it's Lorentz' interpretation of SRT - but Ives has ... With an absolute velocity vector along its length ... If this bar is spinning and has an absolute ...
    (sci.physics.relativity)