Webjal Installed By Harry Thompson

The EJS Magnetic Multipole Field Model shows the field of a magnetic dipole or quadrupole with little compasses that indicate direction and relative field strength. A slider changes the angular orientation of the dipole and a movable compass shows the magnetic field direction and magnitude....

The Ejs Waves and Phasors model displays the motion of a transverse wave on a string and the resulting phasors for the wave amplitude. The simulation allows an arbitrarily polarized wave to be created. The amplitude, period, phase velocity and number of phasors displayed can all be changed via...

The Ejs Transverse Wave model displays the motion of a transverse wave on a string. The simulation allows an arbitrarily polarized wave to be created. The magnitude of the components of the wave and the relative phase between the components of the wave can all be changed via sliders. You can...


Platforms: Mac

The Ejs Resonance in a Driven String model displays the displacement of taut string with its right end fixed while the left end is driven sinusoidally. The driving frequency, amplitude, and the simulation's dt can be changed via text boxes and the motion can be further fine tuned by zooming in...


Platforms: Mac

The EJS Angular Acceleration of a Contracting System model shows a mass and pulley system to illustrate what happens when a rotating system contracts. When the centripetal force has contracted a rotating system to half its initial radius then: (1) The tangential velocity has doubled, (2) The...


Platforms: Mac

The Ejs Spring Pendulum model displays the model of a hollow mass that moves along a rigid rod that is also connected to a spring. The mass, therefore, undergoes a combination of spring and pendulum oscillations. The initial position and velocities, as well as the spring constant can be changed...


Platforms: Mac

The Ejs Two Falling Rods model displays the dynamics of two rods which are dropped on a smooth table. In one case the end point on the table slides without friction, while in the other case it rotates about a pivot point. The simulation allows computing fall times and trajectories. The initial...


Platforms: Mac

The Ejs Quartic Potential Orbit model displays the dynamics of a mass orbiting a much larger mass subject to a quartic potential, C/r4. The simulation displays the motion of the smaller mass and the effective potential energy diagram. The initial energy of the system can be changed via textbox...


Platforms: Mac

The EJS Waveguide model displays the motion of a traveling wave forced to move between two walls in a waveguide. The two walls are located at y = 0 and a, so that its normal modes are u(t,x) = A sin(n ?Y?* y/a) cos(k x - ?Ya* t) with n equal to a positive integer. The phase velocity and number of...


Platforms: Mac

The Ejs Great Circles model displays the frictionless motion of a particle that is constrained to follow the surface of a perfect sphere. The sphere rotates underneath the particle, but since there is no friction, and the sphere is perfectly spherical, the motion of the particle is not influenced...


Platforms: Mac

The Ejs Three Current-Carrying Wires model is a ranking task exercise involving the ranking of the current magnitudes in three parallel current-carrying wires. The simulation displays the net force on each wire because of the other two wires. You can modify this simulation if you have Ejs...


Platforms: Mac

The EJS Slipping and Rolling Wheel Model shows the motion of a wheel rolling on a floor subject to friction. The simulation allows the user to change the initial translational and rotational velocities of the wheel, v and ?Ya*, the mass, radius, and mass distribution, R, m, and C of the wheel. By...


Platforms: Mac

The Ejs Wave Packet model displays the motion of an approximate wave packet. The simulation allows an arbitrarily wave packet to be created. The default dispersion relation, with the frequency equal to the wavenumber, results in a wavepacket that does not spread. The amplitude, maximum and...


Platforms: Mac

The Ejs Superior Ptolemaic model illustrates Ptolemy's orbit for a superior planet. The model consists of a deferent circle, centered on a point some distance from Earth (at the eccentric point). Attached to this deferent is the center of another circle, the epicycle. The center of the epicycle...


Platforms: Mac

The Ejs Action for the Harmonic Oscillator model displays the trajectory of a simple harmonic oscillator by minimizing the classical action. The simulation displays the endpoints of the motion (t,x) which can be changed by using the textboxes or dragging, and displays the new trajectory as well...


Platforms: Mac

The EJS Earth Orbit model illustrates the Copernican theory of Earth's orbit around the sun. The top window shows a view from outside the celestial sphere. The simulation shows the moving Earth along with its axis or rotation and the line of sight from Earth, through Sun, to the Celestial Sphere....


Platforms: Mac

The Ejs Copernican System model illustrates Copernicus' system of planetary motions. The entire system is centered on the center of Earth's uniform, circular orbit. Sun is placed near, but not at, this center point. The orbit of each planet (other than Earth) consists of a deferent circle,...


Platforms: Mac

The Ejs Inferior Ptolemaic model illustrates Ptolemy's orbit for a inferior planet. The model consists of a deferent circle, centered on a point some distance from Earth (at the eccentric point). Attached to this deferent is the center of another circle, the epicycle. The center of the epicycle...


Platforms: Mac

The Ejs Three Charged Particles model displays three charged objects, one at each corner of an equilateral triangle. The charges have different magnitudes - your job is to rank the charges based on their magnitudes, from largest to smallest. You can drag the charges around to see the effect on...


Platforms: Mac

The Ejs Wave Representations model displays two representations of a sinusoidal wave on a string. One shows a movie of the wave traveling along a string - you can think of this representation as a sequence of photographs. The second representation is a plot of the displacement as a function of...


Platforms: Mac