newton/docs/guide/forces.jade

A playful, particle-based physics engine designed from the ground up for JavaScript.

p.
  Forces are the second basic element of Newton.
  Each frame, the Simulator applies Forces to Particles in order to create movement.
p.
  Newton comes with a library of Forces, and you can easily add your own.

pre.CodeBlock.
  var gravity = Newton.LinearForce(1, Math.PI * 1.5);   // strength, direction
  sim.add(gravity);