During an elbow extension exercise, the relative angle at the elbow was $87\mathrm{.}7$ degrees at $1\mathrm{.}86$ seconds and $172$ degrees at $2\mathrm{.}89$ seconds. what was the angular velocity of the elbow rotation? $[$don$\text{'}$t worry about direction for this question $-$ just enter the magnitude of the angular velocity in rad$/$s$]$