Ejs Linear Resistive Force Projectile Motion

This simulation uses Easy Java Simulations (Ejs) to model the problem of a projectile with an initial velocity subject to a resistive force in each direction that is proportional to how fast it is going. The standard two models for velocity-dependent resistive forces are

The Linear Case: the resistive force is proportional to the velocity:

F_x = -b*v_x

and

The Quadratic Case:  the resistive force is proportional to the square of the velocity:

F_x = -b*v_x *v_x ,

which assumes that the particle has an initial velocity in the positive x direction.