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Re: [Phys-L] A force multiplier



On Feb 9, 2013, at 8:23 PM, John Denker wrote:

On 02/09/2013 05:28 PM, Ludwik Kowalski wrote:

How can a force F1=2 N overcome the force F2 equal to 12 N?

It's called mechanical advantage.

It occurs all the time. You ask how can it occur; I ask why
should it not occur? Why should it be considered odd? There
is no such thing as conservation of force.

Yes indeed; the inclined plane, the block and tackle system, the lever, the hydrolic lift, etc, are well known examples.


There is of course conservation of energy. In static mechanics
situations such as this, we have
F1 • dx1 = F2 • dx2

Mechanical consists of F1 being larger than F2 in conjunction
with dx1 being smaller than dx2.

The geometry of the situation determines the ratio of dx1 to
dx2. That plus conservation of energy determines the ratio
of F1 to F2.

=============

Some little kids like to read _The Cat In the Hat_.
http://www.amazon.com/dp/039480001X

I preferred reading _The Big Ball of String_.
http://www.amazon.com/dp/0394900057

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