Category Archives: Physics

Relation between motor’s torque/speed and its voltage/current.

The torque of a motor is proportional to the current flowing through it (). The angular velocity of a motor is proportional to the voltage across it (). Details and derivation here: motor.pdf.

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Line Segment to Circle Collision/Intersection Detection

Style and Notation All variables are represented in italics except in the diagrams and Python code. Vectors are shown in bold except in the diagrams and Python code. The notation |a| is used to represent the length of a vector … Continue reading

Posted in Computational Geometry, Mathematics, Physics, Programming | 6 Comments

Improved RK4 Implementation

This is a Python implementation of the RK4 numerical integrator that works with differential functions of all orders. That is, any function in the form F(x, y, y’, y”, …, ). If you’re new to numerical integration or even RK4 … Continue reading

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Chain

I made a little Processing sketch based on the same physics as JavaScript physics. (View the full post to try it out.)

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JavaScript physics

I made a very basic physics demo in JavaScript to practice using the MooTools library. It uses Verlet integration as outlined in Thomas Jakobsen’s paper. To try out the demo, go to http://doswa.com/projects/physics_js/

Posted in Physics, Programming | 6 Comments

Fourth order Runge-Kutta numerical integration

Here’s a Python implementation of RK4, hardcoded for double-integrating the second derivative (acceleration up to position). For a more generalized solution, see my other implementation. I tried to keep this as simple as I could, so people can easily see … Continue reading

Posted in Mathematics, Physics, Programming | 6 Comments