# Question c8521

Jan 15, 2018

#### Answer:

Technically the absolute value of the velocity is $0$ since the rock is traveling in a circle and it always returns to the same location (remember velocity involves direction as well as speed).
If you really meant to find the speed of the rock, see below.

#### Explanation:

If the radius is $1.2$ m
then the circumference is $2 \times 1.2 \pi \approx 7.346$ m

If the rock covers the $7.346$ m in $2.1$ seconds
then it is traveling at a speed of $\left(7.346 \text{ m")/(2.1} \sec .\right) \approx 3.6$ m/sec.