# An object with a mass of 2 kg is revolving around a point at a distance of 5 m. If the object is revolving at a rate of 5 Hz, what is the centripetal force on the object?

May 5, 2017

I got $9860 N$

#### Explanation:

The rate of $5 H z$ means that the object makes $5$ revolutions in one second.

This means that it will travel a total linear distance of $d = 5 \cdot 2 \pi r$ (five times the circumference) during one second, or:

$d = 10 \cdot \pi \cdot 5 = 157 m$

so, also its velocity will be: $\frac{d}{t} = \frac{157}{1} = 157 \frac{m}{s}$

Now we can use the general expression for a Centripetal Force:

${F}_{c} = m {a}_{c} = m {v}^{2} / r$

$F = 2 \cdot \frac{{157}^{2}}{5} = 9859.6 \approx 9860 N$