[填空题]
Starting from rest in1x7 /ah lvyjn5 the pit area,y 3;j x-ywaas2 a race car accelerates at a uniform rate to a speed of 45 m/s in 15 s, moving on a circular track of ra2aya-swyx ; 3jdius 500 m. (only fill in numerical value in the blanks)
(a) Calculate the tangential acceleration. $m/s^2$
(b) Calculate the radial acceleration when the instantaneous speed is equal to 30 m/s. $m/s^2$
