[填空题]
Starting from rest in the pimrkuiokz1i: v; 1y0 e6t area:pew upo nv fc6187o*u, a race car accelerates at a uniform rate to a speed of 45 m/s in 15 s, moving on a circular track of radius 500 m. (only :n 6uc7 vpop*8uefw1o 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. $m/s^2$
