Subsequently, the LCDs which were further from the center of the circle were traveling faster in order to sweep out the circumference of the larger circle in the same amount of time. With the room lights turned off, the LCDs created an arc which could be perceived to be longer for those LCDs which were traveling faster - the LCDs with the greatest radius. This is illustrated in the diagram above. Objects moving in uniform circular motion will have a constant speed. Recall from Unit 1 of The Physics Classroom that speed and velocity refer to two distinctly different quantities.
Speed is a scalar quantity and velocity is a vector quantity .
Velocity, being a vector, has both a magnitude and a direction. Since an object is moving in a circle, its direction is continuously changing. At one moment, the object is moving northward such that the velocity vector is directed northward. One quarter of a cycle later, the object would be moving eastward such that the velocity vector is directed eastward. As the object rounds the circle, the direction of the velocity vector is different than it was the instant before.