Answer
$w=\frac{9}{5}$ radians per sec
Work Step by Step
Step 1: The formula to be used here is $v=rw$.
Step 2: After substituting the values of $v$ and $r$ provided by the question into this formula, the equation becomes $9=5\times w$
Step 3: Multiplying both sides by $\frac{1}{5}$,
$9\times\frac{1}{5}=5\times w\times\frac{1}{5}$
Step 4: $w=\frac{9}{5}$ radians per sec