Question

An object with a mass of `2 kg` is revolving around a point at a distance of `4 m`. If the object is making revolutions at a frequency of `3 Hz`, what is the centripetal force acting on the object?

Answer 1

I found: `2842N`

Explanation:

Centripetal force is given as:
`F_c=mv^2/r`..............................(1)

We can evaluate the velocity knowing that the object moves of a (linear) distance equal to:
`d=2pir`
and that the frequency (representing the number of turns in one second) is `3Hz` meaning that in one second it will go through `3` complete turns:

So the total liner distance will be:

`d=3*2pir=3*2pi*4=75.4m` in one second corresponding to a velocity (linear):

`v=d/t=75.4/1=75.4m/s`

Using this information into the expression for centripetal force (1) we get:

`F_c=2*(75.4)^2/4=2842N`