On an Amusement Park Ride, Passengers Are Seated in a Horizontal

Multiple Choice

On an amusement park ride, passengers are seated in a horizontal circle of radius 7.5 m. The seats begin from rest and are uniformly accelerated for 21 seconds to a maximum rotational speed of 1.4 rad/s.
-What is the tangential acceleration of the passengers during the first 21 s of the ride?

A) 0.067 m/s²
B) 0.50 m/s²
C) 1.4 m/s²
D) 7.5 m/s²
E) 11 m/s²