[填空题]
Starting from rest in t5oso-,dk0s:6f+cyh faz 3gub he pit area, a r7xm3h ,lzb qpq* (daj)* e)bfnace car accelerates at a uniform rate to a speed of 45 m/s in 15 s e )b(a7zqm*d hxlqf, 3pj*)nb, 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. $m/s^2$
