During a $4\mathrm{.}7$ s time interval, a flywheel with a constant angular acceleration turns through $440$ radians and acquires an angular velocity of $156$ rad$/$s$.($Assume the flywheel is rotating in the positive direction. Indicate the direction with the signs of your answers.$)$

$($a$)$

What is the angular velocity $($in rad$/$s$)$ at the beginning of the $4\mathrm{.}7$ s$?$

rad$/$s

$($b$)$

What is the angular acceleration of the flywheel $($in rad$/$s$2)?$

rad$/$s$2$