Could someone help me with these questions, I am confused.

Question 1 An athlete is looking for a speedy recovery from an injury and has been advised to try bloodsspinning. During this process, a sample of the athlete's blood is put in a centrifuge that needs 7.9 s to speed up from rest to top speed of 1 rotation for every 0.410 s. Ifthe blood sample is 6.16 cm from the centrifuge, what is it's tangential acceleration during the initial 7.9 s? : Question 2 A stuntman drives a dirt bike on a curved track with a radius of 12.8 m. If he starts from rest and accelerates at 2.75 m/s2, at what time will the magnitude of the total acceleration of the bike be 6.09 m/sz? (Hint: the tangential acceleration will stay constant at 2.75 m/s2.)