Find the velocity, $v$, of the tip of the minute hand of a clock, if the hand is $9 \mathrm{~cm}$ long. $v=\square$ cm per minute (Type an exact answer, using $\pi$. Use fractions for any numbers in the equation.)

Step 1 ：The minute hand of a clock completes a full circle, or \(2\pi\) radians, in 60 minutes.

Step 2 ：The distance traveled by the tip of the minute hand is the circumference of the circle it traces, which is \(2\pi r\), where \(r\) is the length of the minute hand.

Step 3 ：Substitute \(r = 9\) into the equation to get the distance: \(2\pi \times 9 = 18\pi\) cm.

Step 4 ：The velocity is the distance traveled divided by the time taken. So, \(v = \frac{18\pi}{60} = \frac{3\pi}{10}\) cm per minute.

Step 5 ：Final Answer: The velocity, \(v\), of the tip of the minute hand of a clock, if the hand is \(9 \mathrm{~cm}\) long, is \(\boxed{\frac{3\pi}{10}}\) cm per minute.