# Uniform Circular Motion Question

1. Homework Statement :
A body of mass 81.7g is moving in a circular path of radius 0.65m. If we calculate the centrifugal force on it to have a magnitude of 0.35N, what is the period of revolution? (2 decimals, UNITS!)(p = 3.14)

2. Homework Equations :
I'm given the following equations:
a = v^2/r
v = Circumference/Period = 2pi/T
a = 4pi^2r/T^2
F = Mg
F = ma
3. The Attempt at a Solution :
I took .35 = mv^2/r so .35 = 81.7v^2/.65 so v = .5276
then I took T = 2pir/v so T = 2pi(.65)/.5276 so T =7.736

I got this wrong when I entered it. I may have rounded wrong at the end or didn't do it right in the first place Any help would be appreciated.

## Answers and Replies

andrevdh
Homework Helper
The supplied mass is in grams.

so I would divide the mass by 1000 then do what i did?

Kurdt
Staff Emeritus
Science Advisor
Gold Member
Seems that way. Always take note of the units in questions and remember that standard formula are for SI units.

andrevdh
Homework Helper
Yes. The S.I. unit of mass is kilograms.