Generating momentum

In our previous recipe we have touched upon force layout node object and its {x, y} attributes, which determine where a node locates on the layout. In this recipe we will discuss another interesting aspect of physical motion simulation: momentum. D3 force layout has built-in support for momentum simulation which relies on the {px, py} attributes on the node object. Let's see how this can be done in the example described in this recipe.

Getting ready

Open your local copy of the following file in your web browser:

https://github.com/NickQiZhu/d3-cookbook/blob/master/src/chapter11/momentum-and-friction.html.

How to do it...

In this recipe we will modify the previous recipe by first disabling both gravity and charge then giving newly added node some initial velocity. As a result now the faster you move the mouse higher the initial velocity and momentum will be for each node. Here is the code to do that:

<script type="text/javascript">
    var force = d3.layout.force()
 ...