Real Physics for the iPad

**Video tutorials/demos available at www.kirkkaminsky.com/RealPhysics/Tutorials**

[Please note that 'Real Physics' is now superceded by the universal app 'Numerical Physics'. Real Physics' is being maintained for legacy devices and versions of iOS 7.1 and earlier.]

Learning or teaching classical physics?  Need to check the numerical answer to a physics homework problem … while you watch the actual physical system visually evolve?  Want to create and project a mechanics simulation you built yourself for your students ... in real time? Or do you just have an uncontrollable desire to simulate and animate realistic physical systems? 


'Real Physics' is the first touch-based, explicitly numerical, real-time, *point-particle* simulator of Newtonian mechanics in two dimensions for iOS devices, built around a custom physics engine.  It can model, animate and numerically solve with high accuracy a wide class of high school and University mechanics problems you set up yourself using its direct, intuitive touch interface and its open-world 'sandbox' design. Whether you're a student who wants to animate and solve an exotic Atwood’s pulley problem, a teacher wanting to show your students the connection between circular motion and simple harmonic motion, or simply someone who wants to numerically simulate an exotic force or multiply-constrained system, this is the one Physics app you must have: it’s like having a calculator of the real world in your hand!
 
Written by a physicist and educator, designed for educators and students of physics.


Features include the ability to:
- dynamically generate free-body diagrams, trajectories, and essentially arbitrary two variable graphs that evolve while the simulation runs, and whose underlying numerical data you can export;
- define, in addition to a standard set of 'explicit forces', essentially arbitrary user-specified position, velocity and time-dependent forces (like inverse square law forces or external driving forces) in terms of Cartesian components, magnitude and direction, or tangential and centripetal components;
- constrain bodies to user-defined constraint curves, surfaces or inclines (with or without realistic friction); 
- connect bodies to each other via springs, direct tension force constraints, indirectly through pulleys, or custom interbody forces you specify. 
- specify a 'halting condition' on any physical property of a body that can be graphed: this means that 'Real Physics' can be used to numerically solve a wide range of problems commonly encountered in high school through second year University mechanics. It can easily model complex systems numerically that cannot be analytically solved with its choice of five different numerical integrators, time-step, frame rate, and simulation rate control. 
- have unconstrained and certain singly-constrained bodies participate in collisions with each other or with a constraint surface, with a user-specified coefficient of restitution, to determine scattering angles and speeds.
- share your worlds with others, and export your numerical data to spreadsheets.

More than 60 examples are bundled with Real Physics that range from the specific numerical solution of old exam/homework type problems in Newtonian mechanics, to pure qualitative simulations (e.g. the three body problem, or Coulomb scattering), to powerful simulations of Lagrangian mechanics constrained problems (like a double or forced pendulum).