Here is another applet about circular motion.
It was designed to illustrate relation/constraint for circular motion: a=V[sup]2[/sup]/R.

[color=red]Red[/color] arrow is the instance velocity $V(t)$,
arrow with color "[color=#f0f]magenta[/color]" is $V(t+dt)$
The [color=blue]blue[/color] arrow is $d\vec{V}=\vec{V}(t+dt)-\vec{V}(t)$ which is always pointing toward the center.
with  $d\theta=V*dt/R$ ,
so It's length $|d\vec{V}|=V d\theta=V* V*dt/R$,
so $\frac{d\vec{V}}{dt}=\frac{V^2}{R}$

/htdocs/ntnujava/ejsuser/2/users/ntnu/fkh/circularmotionavr_pkg/circularmotionavr.propertiesFull screen applet or Problem viewing java?Add http://www.phy.ntnu.edu.tw/ to exception site list