BUTURAKU

Explore physics at your fingertips. 12 sims: gravity, projectile, slope, energy, collisions, pendulums, springs, circular motion, brachistochrone, waves. Ask "what if?"

BUTURAKU is a physics simulation app that lets you explore physical phenomena through real-time animations.

Understand physics laws intuitively with beautiful visuals. Freely adjust parameters with sliders and observe how physical phenomena change in real time.

12 Simulations:

[Translational motion]

• Free Fall: Observe the effects of gravity and air resistance. Tap to add balls, swipe to throw them.
• Projectile: Adjust launch angle, initial speed, and air resistance to observe parabolic motion.
• Inclined Plane: Motion on a surface with friction. Experience sliding conditions by changing angle and friction coefficient.
• Brachistochrone: Race three balls down line, arc, and cycloid tracks under gravity. Bernoulli's classic 1696 problem - the cycloid wins.
• Energy Conservation: A ball rolls along a roller-coaster track while kinetic and potential energy swap places. Turn on friction to see mechanical energy dissipate into heat.
• Collision: 2D collisions based on conservation of momentum and kinetic energy. Momentum vector display available.

[Oscillation and periodic motion]

• Pendulum: Nonlinear pendulum with high-precision RK4 integration. Drag to set the angle.
• Double Pendulum: Coupled pendulums producing chaotic motion. Lagrangian mechanics + RK4.
• Coupled Pendulum: Two pendulums joined by a spring exchange energy periodically — the classic beat phenomenon.
• Spring: Simple harmonic motion with Hooke's law. Adjust spring constant, damping, and mass.
• Circular Motion: Uniform circular motion with centripetal force visualization (F = mω²r). Adjust radius, angular velocity, and mass.

[Waves]

• Wave: Tap to place wave sources and observe interference patterns. 2D wave equation solved numerically with finite differences.

[Features]

• Real-time physics simulation
• Intuitive touch controls
• Freely adjustable parameters via sliders
• Physics explanations for each simulation
• Dark / Light theme support
• Japanese and English language support