http://www.ahhsmassage.com/sheet-set-natural/
Sheet Set Natural
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Elation™ US Made Flannel Sheet Set - Natural
$48.00 |
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Charm™ 100% Cotton Massage Sheet Set - Natural
$29.95 |
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Poly/Cotton Massage Sheet Set & Face Cover-Natural
$20.00 |
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Poly/Cotton Massage Sheet Set & Face Cover-Natural-5 pk
$92.50 |
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Poly/Cotton Massage Sheet Set & Face Cover-Natural-10pk
$176.00 |
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Poly/Cotton Massage Sheet Set & Face Cover-Natural-50pk
$880.00 |
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NRG Energy Massage Tables Natural 100% Cotton Flannel Sheet Set Brand New!
$12.99 |
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50 pk Comfort™ Flannel Massage Sheet Sets -Natural
$1,080.00 |
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10 pk Comfort™ Flannel Massage Sheet Sets -Natural
$240.00 |
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Comfort™ Flannel Massage Sheet Sets -Natural-
$22.50 |
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Flannel Sheet Set
$14.50 |
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5 Pack Comfort™ Flannel Massage Sheet Sets -Natural-
$125.00 |
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BodyWorks Massage Table Flannel Sheet Set - Natural
$31.95 |
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Flannel Sheet Set (Qty of 6 Sets)
$78.00 |
How to find the natural length of a spring with given, constant force, radius, mass and revolutions?
A ball with mass of 0.1kg rests on horizontal sheet of essentially frictionless ice. It is attached by a spring with constant force of 80 N/m to a post set in the ice. Once given push, the ball revolves uniformly in circle with radius 0.5 m around the post. If the ball revolves makes 2 complete revolutions in 1 s, find the natural length for the spring.
Notice that the ball is moving in a circle.
_Anything_ that moves in a circle (at constant speed) has an acceleration equal to this amount:
a = ω²r
(where ω = its angular velocity, and r = its distance from the center of the circle).
Therefore, the net force on the ball is:
F_net = ma = mω²r
But this force is supplied entirely by the spring. That is, the spring must be stretched just enough to supply a force of mω²r.
F_spring = mω²r
But F_spring is also equal to the spring constant (k) times the amount of stretch (x). That means:
F_spring = kx = mω²r
Now, x and r and the “natural length” of the spring (call it L) are related as follows:
r = (natural length) + (amount of stretch)
r = x + L
So that means you can get rid of “x” in the previous equation by replacing it with “r – L”:
k(r-L) = mω²r
The problem gives you “k” and “r” and “m” directly. You can calculate “ω” by converting (2 revolutions/sec) into radians per second.
Then all you need to do is solve for “L”.
