Discussion:
Energy used in a horizontal hold - timed weightlifting
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Dave
2024-07-08 11:12:29 UTC
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Here's a very simple question:
How do you calculate the energy used by a sportsperson with a timed
horizonal hold? You hold out a 10kg kettlebell (women) or a 18kg
kettlebell (men) horizontally in front of you for as long as possible,
and the person who hold it out longest wins.

Obviously the longer you hold, the harder it gets until it's torture
from lactic acid build up, and you give up.

The physics I've been taught has no anwser, since energy is newton
meters. I'm politely suggesting that the energy unit needs a
rework to include time, and per relativity spacetime.

Said spectacle isn't in competition so much, too many awkward
questions? Answer from bad or stupid teachers is:
"You're not making any sense. Energy is force times distance".

Some videos talk about specific impulse, which is force times
time, but this isn't worked into anything else.

To make the competition even between long arm and short arm people,
it may be fairer to hold it out for a set distance, not with
locked elbows.
Jim Pennino
2024-07-08 15:53:16 UTC
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Post by Dave
How do you calculate the energy used by a sportsperson with a timed
horizonal hold? You hold out a 10kg kettlebell (women) or a 18kg
kettlebell (men) horizontally in front of you for as long as possible,
and the person who hold it out longest wins.
Obviously the longer you hold, the harder it gets until it's torture
from lactic acid build up, and you give up.
The physics I've been taught has no anwser, since energy is newton
meters. I'm politely suggesting that the energy unit needs a
rework to include time, and per relativity spacetime.
Said spectacle isn't in competition so much, too many awkward
"You're not making any sense. Energy is force times distance".
Some videos talk about specific impulse, which is force times
time, but this isn't worked into anything else.
To make the competition even between long arm and short arm people,
it may be fairer to hold it out for a set distance, not with
locked elbows.
You are conflating physics and physiology.

Replace the biological entity with a wooden cross and you have the
answer from physics, i.e. zero energy is used.

To get an answer from physiology you need to understand how muscles
work.
bertietaylor @novabbs.com (bertietaylor)
2024-07-09 08:33:26 UTC
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Post by Dave
How do you calculate the energy used by a sportsperson with a timed
horizonal hold? You hold out a 10kg kettlebell (women) or a 18kg
kettlebell (men) horizontally in front of you for as long as possible,
and the person who hold it out longest wins.
Obviously the longer you hold, the harder it gets until it's torture
from lactic acid build up, and you give up.
The physics I've been taught has no anwser, since energy is newton
meters. I'm politely suggesting that the energy unit needs a
rework to include time, and per relativity spacetime.
Said spectacle isn't in competition so much, too many awkward
"You're not making any sense. Energy is force times distance".
Some videos talk about specific impulse, which is force times
time, but this isn't worked into anything else.
To make the competition even between long arm and short arm people,
it may be fairer to hold it out for a set distance, not with
locked elbows.
Energy is force times distance so in your case while there is force it
does not move anything so energy expended is zero.
The force causes the muscles to tire.
Dave
2024-07-09 09:37:48 UTC
Permalink
Post by Dave
How do you calculate the energy used by a sportsperson with a timed
horizonal hold? You hold out a 10kg kettlebell (women) or a 18kg
kettlebell (men) horizontally in front of you for as long as possible,
and the person who hold it out longest wins.
Obviously the longer you hold, the harder it gets until it's torture
from lactic acid build up, and you give up.
The physics I've been taught has no anwser, since energy is newton
meters. I'm politely suggesting that the energy unit needs a
rework to include time, and per relativity spacetime.
Said spectacle isn't in competition so much, too many awkward
"You're not making any sense. Energy is force times distance".
Some videos talk about specific impulse, which is force times
time, but this isn't worked into anything else.
To make the competition even between long arm and short arm people,
it may be fairer to hold it out for a set distance, not with
locked elbows.
After thinking about this some more, it's not so easy. Obviously you
are using energy, from the force you need to apply, or otherwise.
Not adding energy to the kettlebell.

Best to reformulate the problem and use calculus. The reformulation
is to assume you're moving the weight up in an semicircle arc,
180 degrees, and take results from the force at the pivot,
i.e. your shoulders. Then use calculus to see the power in watts
for the lift needed when your arms are horizontal, and multiply this
by time.

A very interesting question in a 3 hour exam, this being one of the
three quesions. The marks and time given is the only hint it's
not a two line answer in words. Not reformulation, just the original
on the exam paper. Depending on the culture, might be the homework
for the week.

You don't get TV to this level in edutainment programmes in the UK,
(or US?), but Indian English language programming? They don't mind
equations in the Times of India (as 2006).

Haven't done the sums, might be a good question for AI. E.g. if
you're not wanting it too smart, nothing ever gets typed into a
computer, or digital photos taken by recent devices. A pre 2009
compact camera and an old pre 2004 desktop (not networked),
if in a well screened Faraday cage with an independent power
supply, may be OK. Use a typewriter?

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