The equations of kinematics describe the motion of an
objectthat has a constant accleration. these equations cannot
beapplied to uniform circular motion. why not?

The equations of kinematics is applied for the motion with constant acceleration (including zero), but the condition is that the acceleration should be in the direction of the motion (positive or negative).

In circular motion, the acceleration is radial (centripetal), which means that the acceleration is always perpendicular to the motion of the object, therefore the equations of kinematics cannot be applied.  

lexy is right because she has the labeled s

0.11 m/s and 0.28 m/s should be correct