The falling 3D Particle model shows a three-dimensional view of a falling ball.
An Introduction to Computer Simulation Methods
Chapter 3 Examples: Simulating Particle Motion
The following EJS models are described in Chapter 3 of the EJS adaptation of An Introduction to Computer Simulation Methods.
- SHO Euler The SHO Euler model solves the first-order differential equations for a particle attached to a Hooke's law spring using Euler's method.
Euler's method is implemented explicitly on the Evolution workpanel in order to teach Java syntax. We use Euler's method to study the simple harmonic
oscillator (SHO) because its analytic solution is well known and because its constantly varying acceleration produces easy to detect numerical errors
without multi-variable force expressions.
- SHO ODE Solver The SHO ODE Solver model demonstrates how to use the EJS ODE editor to solve a differential equation. Examine this model in
\ejs\ and right-click on the Evolution workpanel tabs to enable and disable pages to test algorithms. The explicit evolution page is disabled and the ODE
editor page is enabled in the default configuration.
- Falling Particle The Falling Particle model shows a falling ball and plots its position as a function of time. The ball falls with constant
acceleration and click-dragging on the ball changes its height but leaves its velocity unchanged. The reset button stops the animation and sets the initial
conditions. Users are encouraged to analyze the position data using the Data Tool. This model is a starting point for the exercises and problems in this
chapter. Users can, for example, enable the zero crossing event in the Evolution workpanel to compute the maximum height of the particle.
- Falling 3D Particle The Falling 3D Particle model simulates the physics free fall with a 3D view. The ball falls with constant
acceleration in the z direction. Click-dragging on the ball changes its height but leaves its velocity unchanged. The reset button stops the simulation
and sets the initial conditions. An ODE event is used to reverse the velocity when the ball reaches the floor and the coefficient of restitution reduces
the speed of the ball after the bounce. The time between bounces decreases but this "Zeno effect" is resolved by removing the acceleration if the ball is
resting on the floor.
Download
An Introduction to Computer Simulation Methods examples are distributed as a ready-to-run (compiled) Java archive. Double clicking the
csm_ch03.jar file will run the chapter 3 examples if Java is installed. You can examine and modify the model for
these examples if you have EJS installed by right-clicking within the program and selecting "Open Ejs Model" from the pop-up menu.