need to have discussion with teacher F2F before i implement the changes

1) Can we have the arrow scale slider permanently displayed, instead of hiding in the green check box?
[color=blue][b]added permanent on the left[/b][/color]


2) Can we have the two arrows along the same line, instead of one above another?
[color=blue][b]the purpose is to allow visualization when both are perfectly align it is hard to see.
i make it slightly apart still acting of the particle, should be better now.[/b][/color]


3) Can we also hide Mass 1 and display only Mass 2? This will help students observe the individual g and potential graphs before they observe the net g and potential graphs.
[color=blue][b]agree, done [/b][/color]


4) Can we have a button to hide the g field arrows? So that the arrows won't confuse the students when they are observing the potential graphs.
[color=blue][b]agree, done [/b][/color]

5) Is it necc to have the Fnet and Unet? I suggest remove the green and transparent check boxes.
[color=blue][b]to complete the computer model to allow inquiry into the Fnet and Unet.
i recommend keep them for students to understand [/b][/color]


6) Can we indicate 'g' beside the g graph check box? same for potential graph check box.
[color=blue][b]agree, done [/b][/color]


7) Mass 1 and Mass 2 sliders and display boxes are just next to each other and the same blue colour may make it difficult to differentiate. Can you demarcate the two with a thick solid line.
[color=blue][b]agree, done [/b][/color]


8) Can we have a button to display a tangent for potential graph? The gradient of tangent should be equal to the - (g value). Good to display the value of gradient and g value simultaneously for comparison.  
[color=blue][b]agree, done [/b][/color]
[color=blue][b]made dV/dr = to show to be compare to g.
for realization of dV/dr = - g.
the minus sign is to be included by students to deepen thinking.[/b][/color]