An object with a mass of 6kg is revolving around a point at a distance of 8m. If the object is making revolutions at a frequency of 2Hz, what is the centripetal force acting on the object?

1 Answer
Feb 17, 2016

I found: 7580N

Explanation:

Centripetal Force is:
Fc=mv2r
where:
m=mass;
v= linear velocity;
r= radius.

The frequency tells us the number of complete revolutions in one seconds (here 2 revolutions).
We can ask ourselves what will be the Angular Velocity ω of our object, i.e., a kind of "curved" velocity involving not linear distance but angle described in time!

So we get:

ω=angletime=2πT

Where T will be the Period of time for a complete revolution (time to describe 2π radians).

The good thing is that the period is connected to frequency as frequency=ν=1T
and also the angular velocity can be changed into linear velocity simply considering at what distance from the center you are travelling....(basically, you include the radius)!!!!
so:
v=ωr

in our case we get (collecting all our stuff):

Fc=m(ωr)2r=mω2r=m(2πν)2r=6(23.142)287580N