Answer
Please see the work below.
Work Step by Step
We know that the average speed is given as
$\omega_{avg}=\frac{\omega_i+\omega_f}{2}$
We plug in the known values to obtain:
$\omega_{avg}=\frac{5800+0}{2}=2900rpm$
Now we can we find the number of revolutions as
$N=(2900rpm)(\frac{2s}{60minute})=97revolutions$
