[填空题]
Starting from rest i --4k lilhmumqkb.+ e6n t ik*+v h7w x/jgmwvh5y80p 5vrhe pit area, a race car accelerates at a uniform rate to a speed of 45 m/s in 15 s, mym h0v/j gv5*ihv 85+wk 7rpwxoving 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. $m/s^2$
