discussion with another teacher lim e.p.

[b][color=blue]1 there is a checkbox for velocity that switches the arrows.[/color][/b]
The arrow does not agree to the sign of velocity. There is no checkbox.
[color=blue][b]teacher was using an earlier version.[/b][/color]

[b][color=blue]2 the data up ok. i go play first
what is the name of the ipad app?[/color][/b]
.Mass in motion (quite user friendly)

3. the sliders are already grouped together, maybe i bordered thicker
could you section up the mass, velocity of one mass? top and bottom

because of this teacher's suggestion, the applet is improved to