This animation seems to present a paradox. [br][br]A green dot is placed on the outer rim of a wheel.[br]A blue dot is placed on the inner radius of the wheel.[br][br][You can change the size of the inner radius by dragging the BLUE dot.][br][br]Run the animation - do you see the difficulty ?[br][br]How can you explain the problem?

Adapted from an applet by John Golden