Initial velocity is always specified to a single node and can carry only one value. Multiple initial velocity definitions for the same node will always use the last encountered value. To illustrate this, if we have nodes N1,N2 and N3 and we define a initial velocity for all nodes to be ‘V1’ followed by N2 to have a velocity of 0 followed by N3 to have a value of ‘V3’, the final velocities for the nodes will be N1->V1, N2->0, N3->v3.