Question

An object with a mass of `7 kg` is revolving around a point at a distance of `7 m`. If the object is making revolutions at a frequency of `9 Hz`, what is the centripetal force acting on the object?

Answer 1

OK, there are two equations for centripetal force, both useful, we need the one that has `omega` in it as we are given a frequency, not a linear velocity.

Explanation:

The equations are:

`F = (mv^2)/r` and `F = momega^2r` where `omega = 2pif` and is called the angular velocity (but confusingly, also the angular frequency.)

First, we find `omega = 2pif = 2xx3.14xx9 = 56.52` rad/s

Next the force, `F = momega^2r = 7xx(56.52^2) xx 7 = 156 531`N

I’d quote this as `F = 160,000`N given the data you have.