2. Use the same reasoning as in Lab 8 with angular variables to make a similar statement about the
conditions under which angular momentum is conserved.
3. A person swings a ball of mass $m$ around their head
at speed $v$ and radius $R$ as depicted to the right. They
then pull the string so that the radius decreases from $R$
to $r < R$. In both cases, there is an angle $\theta$ between
the string and the vertical, but it is small enough that we
can ignore it for simplicity. When the person pulls the
string in, does the force exerted on the string produce
any torque on the ball? Explain.
4. Determine the initial angular velocity of the ball $\omega_i$ in terms of $v$ and $R$.
5. Determine the ball's angular momentum $L$ before the person pulls the string in terms of $m$, $v$, and $R$.
6. Once the string is pulled, does the angular velocity change? Explain.