The angular position of a point on a rotating wheel is given by $=4\mathrm{.}82+5\mathrm{.}31t^2+2\mathrm{.}84t^3,$ where $$ is in radians and $t$ is in secands$.$ At $t=0,$ what are $($a$)$ the point's angular position and $($b$)$ its angular velocity? $($c$)$ What is its angular velocity at $t=6\mathrm{.}22$ s$?($d$)$ Calculate its angular acceleration at $t=2\mathrm{.}15s.($e$)$ Is its angular acceleration constant?