Question

The Gravitron is a ride that rotates around a central axis until it reaches a certain velocity and the riders are pinned to the walls. Once this occurs, the floor is lowered until the riders are suspended above the floor. The Gravitron has a radius of 3.00 meters and reaches a speed of 15.0 m/s. Dalnita has a mass of 55.0 kg. What is her angular velocity in radians per second?

Answer 1

Sounds like you've been given some unnecessary information. 
The linear velocity "v" and angular velocity "w" of something in circular motion of radius "R" are related as; 

v = Rw 

You are given v= 15 m/s and R = 3 m , so just solve for "w".

Answer 2

Answer:

Angular velocity of Dalnita, $\omega=5\ rad/s$

Explanation:

It is given that,

The radius of Gravitron, r = 3 m

Speed of gravitron, v = 15 m/s

Dalnita's mass, m = 55 kg

We need to find her angular velocity. The relationship between the angular velocity and linear speed is as follows :

$v=r\times \omega$

$\omega=\dfrac{v}{r}$

$\omega=\dfrac{15\ m/s}{3\ m}$

$\omega=5\ rad/s$

So, her angular speed is 5 radian per second. Hence, this is the required solution.