[填空题]
Starting from rest in the pit area, a racguqsgbjv;2 1881b o yte car accelerates at a r gpnl5k/x 4 p+:d3clyuniform rate to a speegl3c 45y/r:dk +p xnpld of 45 m/s in 15 s, moving on a circular track of radius 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. $m/s^2$
