# Centrifigal Force

RanMan
I am currently try to figure out the amount of pressure on a moving part that weights about an 1/2 oz. It spins at a rate of 285 rpms around the outside of a 4 inch cylinder.
I'm sure there has to be a formula of some sort that can assist in this calculation. Thanks for any help you may be able to give.

Thanks,
RanMan
www.prewettmills.com[/URL]

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Janus
Staff Emeritus
Gold Member
F= Mv²/r

where M is the mass of the object,

v is it's velocity

You'll have to convert oz to mass units and find the object's velocity from the radius and rpm.

RanMan
Janus, I appoligize for the detailed questions but I know absolutely nothing about physics.
I do not know how to determine the velocity nor do I know how to convert ounces to mass. I'm sorry for not knowing a thing about physics.
All I know is the information that i need which is the force.

Thanks,
RanMan
www.prewettmills.com[/URL]

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Janus
Staff Emeritus
Gold Member
Well the unit of mass in the FPS system is the slug, and a one slug mass would weigh 32.175 lbs, and there are 16 ounces to a lb.

so mass = 1/(32.175x16)/2 = .0009625 slug.

The circumfernce of a circle of radius 4 in. is 2*4* pi = 25.13 in. or 2.094 ft.

This is the distance the object travels in one revolution. it does this 285 times per min, so its velocity is 2.094*285 = 596.79 ft/min.

divide this by 60 to get ft/sec for 9.9465 ft/sec and you have v

thus
r = .33333 ft
M= .0009625 slugs
v= 9.9465 ft/sec

plug them in to the formula, and you'll get the force in pounds.