# Centripetal force

1. Oct 28, 2004

### Physics

I have this question for physics and I can't figure it out! A person who weighs 35.0 kg rides a theme park ride. If the ride starts at rest and reaches angular speed of 1 radian/sec in 14sec. The angular acceleration would be .071 rad/sec^2 (i think-haha). Now if the angular speed remains constant until it starts to brake (angular speed becomes half) How many complete rotations if the ride lasts for 2.25 minutes?

2. Oct 29, 2004

### Galileo

Calculate the number of radians passed during the first 14 seconds of angular acceleration:
$$\Delta \theta = \frac{1}{2}\alpha t^2[/itex] Then you have 2.25 minutes - 14 seconds of constant angular velocity. [tex]\Delta \theta = \omega t$$

I`m assuming the ride comes to a grinding halt after this period. I couldn't understand the '(angular speed becomes half)' when braking starts - part.