A body of mass 9 kg moves in a (counterclockwise) circular path of radius 5 meters, making one revolution every 9 seconds. You may assume the circle is in the xy-plane, and so you may ignore the third component.

Compute the centripetal force acting on the body. (As a vector of 2 components.)

I know the first part of the two components, but I need help solving for the last parts.

$\displaystyle <[(-9(10\pi/9)^2) / 5][cos((10\pi/9)t) / ... ], [(-9(10\pi/9)^2) / 5][sin((10\pi/9)t) / ... ]>$

Please help!