Frames Of Reference
B R Sitaram
Zeal Educational Services Pvt. Ltd., Ahmedabad, India
What is Frames of Reference?
Frames of Reference (FOR) is a program that shows you how events transform from one reference frame to another. The program is based on Galilean Relativity; no relativistic effects are included. FOR uses three basic components: two frames of reference and an object. The two frames of reference move with regard to each other; the motion of the object with regard to the first frame is set by the user. The program then computes and displays the motion of the same object as seen in the second frame.
Click here to run the simulation!
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Setting Parameters in Frames of Reference
You can set the following parameters in FOR:
- Object Parameters:
Linear Parameters:
- Initial x and y coordinates (x0, y0, range: -200 to 200)
- initial x and y velocity components (ux0, uy0)
- x and y components of acceleration (ax, ay)
Rotation Parameters: Rotation takes place around the object's centre.
- Initial angle, phi0 (degrees)
- Angular velocity, wp (cycles/sec)
Revolution Parameters: Revolution takes place around the origin.
- Initial angle, theta0 (degrees)
- Angular velocity, wt (cycles/sec)
- Frame Parameters:
Linear Parameters:
- Initial x and y coordinates (x0, y0, range: -200 to 200)
- initial x and y velocity components (ux0, uy0)
- x and y components of acceleration (ax, ay)
Rotation Parameters: Rotation takes place around the object's centre.
- Initial angle, phi0 (degrees)
- Angular velocity, wp (cycles/sec)
Revolution Parameters: Revolution takes place around the origin.
- Initial angle, theta0 (degrees)
- Angular velocity, wt (cycles/sec)
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Reading and Saving Parameters
Parameters can be saved and read as CSV (comma separated strings). Create a CSV consisting of all the parameters in the correct sequence, separated by commas. Copy-paste the string in the "Direct Data Entry" area, in the box labelled "Paste CSV string containing values here:" and click on the "Fill" button. The parameters will appear in the first two columns of the table. You can now edit the values or run the Simulation (see below).
Once a simulation is run, the same box contains the parameter values used for the last run. These can be copied and saved in a text file for later use.
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Plotting and viewing
While plottng and viewing the motion of the object, you can set the following options:
- Time interval between two steps in simulation
- No of steps used in simulation
The left pane shows two sets of points:
- The position of the object in frame 1
- The position of the origin of frame 2 in frame 1.
The right pane shows one set of points:
- The position of the object in frame 2.
Use "Clear Canvas" to clear all drawings.
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Some useful parameter sets
Here are some useful parameter sets for exploration. You can use the csv string given here to run the simulation.
- Two cars approaching one another:
- Two cars following each other:
- Rain seen from moving car:
- Falling object seen from moving car:
- Retrograde motion (Venus from Earth)
- Retrograde motion (Mars from Earth)
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About us
Zeal Educational Services Pvt. Ltd. is a consultancy firm run by Dr. B R Sitaram and Sandhya Sitaram, working with schools, teachers and students in India. We regularly conduct programs in science and maths and design, manufacture and sell science and maths toys and kits. A unique feature of our work is the Computer Club being run in Ahmedabad. To know more about us, click here. Click here to know more about our toys and kits.
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