A figure skater begins spinning counterclockwise at an angular speed of $4\mathrm{.}4ra\frac{d}{s}.$ During a $5\mathrm{.}0s$ interval, she slowly pulls her arms inward and finally spins at $7\mathrm{.}2ra\frac{d}{s}.$

What is her average angular acceleration during this time interval?

Answer in units of $ra\frac{d}{s^2}.$