# BUTURAKU — Feel the beauty of physics

> Feel the beauty of physics (iPhone/iPad app by Fuji Bit Inc..)

- Source: https://appshunter.io/ios/app/buturaku/id6759213255 (this page in markdown: same URL + `.md`)
- Developer: [Fuji Bit Inc.](https://appshunter.io/developer/1874205957)
- Category: Education, Entertainment
- Price: Free
- Age rating: 4+
- Requires: iOS 13.0 · 24 MB
- Languages: Japanese
- Released: 2026-03-28
- Data updated: 2026-06-13
- User reviews in markdown: https://appshunter.io/ios/app/buturaku/id6759213255/reviews.md

## What is BUTURAKU?

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


## Version history (last 5 releases)

### 5.2 — 2026-06-05

- Added an About dialog showing the version and copyright.
- Added a copyright line at the bottom of the home screen.
- Tightened home-screen card padding for stable layout on narrow displays.

### 5.1 — 2026-05-23

- Added an About dialog showing the version and copyright.
- Added a copyright line at the bottom of the home screen.
- Tightened home-screen card padding for stable layout on narrow displays.

### 4.1 — 2026-04-27

We have fixed the bug.

### 3.1 — 2026-04-03

We have fixed the bug.

### 3.0 — 2026-03-28

- New simulation: Spring (Hooke's Law)
- New simulation: Inclined Plane (with friction)
- English language support (auto-switches based on device language)

## More apps by Fuji Bit Inc.

- [SUUGAKU](https://appshunter.io/ios/app/suugaku/id6759102221)
- [PAKEDOU](https://appshunter.io/ios/app/pakedou/id6759820254)
- [OKURERUNA！](https://appshunter.io/ios/app/okureruna/id6759956971)
- [HARAKU](https://appshunter.io/ios/app/haraku/id6759958253)
- [KORAKU](https://appshunter.io/ios/app/koraku/id6760215571)

All apps by Fuji Bit Inc.: https://appshunter.io/developer/1874205957

## Related topics

[buturaku](https://appshunter.io/ios/topics/buturaku)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-13.*