Step-by-step explanation:
Given that,
Initial speed, u = 0
No of rotation is 1 in every 1.2 s
The astronaut is strapped into a seat 4.00 m from the axis, r = 4 m
(a) Let
is the angular acceleration during the first 40 s. It is given by :






Tangential acceleration is given by :



(b) Let a is the centripetal acceleration. It is given by :



Since,


Hence, this is the required solution.