Say I force a cat to move in a circle of radius 10 m clockwise; let's say it takes 11 seconds for the cat to go around the circle for the first time, 12 seconds for the second time, 13 seconds for the third time and so on, and the cat completes 20 laps of the circle until it becomes exhausted and I let it take a rest. Since moving in a circle means the direction always changes, is the cat constantly 'accelerating' even when the speed is decreasing? If so, how do you work out the acceleration/deceleration (in terms of both change in speed and direction), or is it even possible to do so?