# What is the angular momentum of an object with a mass of 5 kg that moves along a circular path of radius 4 m at a frequency of  4 Hz ?

## I

Sep 9, 2016

I'll illustrate it below.

#### Explanation:

The mass of the object is $m = 5 k g$ and radius of the path is $r = 4 m$.

Now, frequency is $f = 4 H z$
But, we know that, angular frequency $\omega = 2 \pi f$

Thus, $\omega = 8 \pi$ $r a \mathrm{di} a n$ ${s}^{-} 1$

Now, we have the relation from elementary dynamics that,

$L = I \omega$ where $I$ is the magnitude of the moment of inertia about the concerned axis.
Further, $I = m {r}^{2}$ which implies that $L = m \omega {r}^{2}$

We have now deduced an expression for the angular momentum $L$ in terms of mass $m$, angular velocity $\omega$ and radius of path $r$.

All you have to do now is plug in the values and get the final result. I won't be doing it for you though.
I'm leaving it as an exercise.

I hope it helped.