Finally! Solved. Below is the more generic version which avoids PhysiJS. Just subsitute three's vectors with those of PhysiJS's.
scene.add(point2);
scene.add(pointAxis);
pointAxis.add(point);
angularVelocity = new THREE.Vector3( 0, 0, 0.01);
function animate(){
// rotate point around pointAxis
pointAxis.rotation = pointAxis.rotation.add(angularVelocity);
// calculate position of point in world space
var pointPosWorld = pointAxis.localToWorld(point.position.clone());
// calculate position of point in world with respect to fulcrum
var pointOffsetPos = new THREE.Vector3();
pointOffsetPos = pointPosWorld.sub(pointAxis.position.clone());
// Calculate tangential velocity
tangentialVelocity = rotate.clone().cross(pointOffsetPos);
}
I arrived at the above thanks to answer here asked in the physics stack exchange site.