You can drag points [b]A[/b] and [b]B[/b].[br]Change the velocity by activating [b]Velocity box[/b]. [br]Change the mass of the balls by dragging the sliders [color=#0000ff]m1[/color] and [color=#38761d]m2[/color]. [br]Activate the [b]Momentum box [/b]to show vectors.