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apinder80
10-21-1999, 10:51 PM
Mel

The distance the ball goes will depend on the impulse imparted to it
(force x time), ie the change in momentum. Therefore it depends upon
the rate upon which work is done to the ball, ie the power. The
power-velocity curve of muscle shows that power (force x velocity) is
zero at zero velocity and zero at maximum velocity (zero power) with a
peak somewhere in the middle. This fits the behaviour you describe.

Also I thought that maximum force occurred under eccentric conditions,
not isometric. Has someone demonstrated otherwise?

Andrew

Andrew.Pinder@hsl.gov.uk, PhD, MSc, Eur Erg, MErgS
Ergonomics and Work Psychology Section
Health and Safety Laboratory, Broad Lane, Sheffield, S3 7HQ, UK
Tel +44 114 289 2594; Fax +44 114 289 2526
HSE home page: http://www.open.gov.uk/hse/hsehome.htm



______________________________ Reply Separator _________________________________
Subject: PP126: F-V PARADOX
Author: at INTERNET-GATEWAY
Date: 21/10/1999 05:58


PUZZLE & PARADOX 126

[snip]

PP 126 FORCE-VELOCITY PARADOX

Here is an apparent paradox which concerns the force-velocity relationship
which describes how force and velocity are interdependent in human movement.
The relationship between force and velocity is seemingly well known. Maximum
force is developed at (or close to, according to more recent research) zero
velocity, i.e. under isometric conditions. Maximum velocity is attainable
only if the load to be overcome is very small.

[snip]

Our experiment is to find out which mass of ball can be thrown the furthest.

You will find, apparently contrary to the theory, that the lightest ball will
not be thrown the furthest. The honour will be bestowed upon a ball that is
somewhere in between the lightest and heaviest balls. You can try this for
yourself by throwing a normal table tennis ball and throwing a series of
table tennis balls filled with sand, lead shot and fillings of other
densities through a small hole drilled into it. Explain this apparent
paradox.



[snip]

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