At a time \( t=2.70 \mathrm{~s} \), a point on the rim of a wheel with a radius of \( 0.180 \mathrm{~m} \) has a tangential speed of \( 48.0 \mathrm{~m} / \mathrm{s} \) as the wheel slows down with a tangential acceleration of constant magnitude \( 10.5 \mathrm{~m} / \mathrm{s}^{2} \).
Part A
Calculate the wheel's constant angular acceleration.
Express your answer in radians per second squared.