Crate use_rotation

Expand description

§use-rotation

Rotational motion, angular momentum, and moment-of-inertia helpers for RustUse.

§Install

[dependencies]
use-rotation = "0.0.1"

§Foundation

use-rotation provides small f64-first helpers for rotational motion and rotational dynamics.

Inputs are expected to be SI-style numeric values:

radians for angular displacement
radians per second for angular velocity
radians per second squared for angular acceleration
meters for radius and length
kilograms for mass
kilogram square meters for moment of inertia
kilogram square meters per second for angular momentum
joules for rotational kinetic energy
newton-meters for torque

The crate does not define a full unit system.

Vector operations should live in or compose with use-vector.

Torque-specific scalar helpers belong in use-torque.

§Example

use use_rotation::{
    AngularState, RotatingBody, angular_velocity, rotational_kinetic_energy,
    solid_disk_moment_of_inertia, tangential_speed,
};

assert_eq!(angular_velocity(10.0, 2.0), Some(5.0));
assert_eq!(tangential_speed(3.0, 2.0), Some(6.0));
assert_eq!(solid_disk_moment_of_inertia(2.0, 3.0), Some(9.0));
assert_eq!(rotational_kinetic_energy(4.0, 5.0), Some(50.0));

let body = RotatingBody::new(4.0, 5.0).unwrap();
assert_eq!(body.angular_momentum(), Some(20.0));

let state = AngularState::new(1.0, 2.0)
    .unwrap()
    .advanced_by_constant_acceleration(3.0, 4.0)
    .unwrap();

assert_eq!(state.angular_position, 33.0);
assert_eq!(state.angular_velocity, 14.0);

§When to use directly

Choose use-rotation when you need small, reusable helpers for scalar angular motion, angular momentum, rotational energy, centripetal relations, and common moments of inertia.

§Scope

APIs stay f64-first and focus on scalar rotational helpers.
Higher-dimensional vector operations should live in or compose with use-vector.
Broad torque-specific helper APIs belong in use-torque.
Full rigid-body dynamics, tensors, and simulation engines are out of scope.

§Status

use-rotation is a pre-1.0 crate with a deliberately small API.

Modules§

prelude: Convenient re-exports for the public rotation helpers.

Structs§

AngularState: A scalar angular position and angular velocity pair.
RotatingBody: A rotating body with scalar moment of inertia and angular velocity.

Functions§

angular_acceleration: Computes angular acceleration using α = (ω_final - ω_initial) / t.
angular_acceleration_from_torque: Computes angular acceleration from torque using α = τ / I.
angular_displacement: Computes angular displacement using θ = ω_initial * t + 0.5 * α * t².
angular_momentum: Computes angular momentum using L = Iω.
angular_velocity: Computes angular velocity using ω = Δθ / t.
angular_velocity_from_angular_momentum: Computes angular velocity from angular momentum using ω = L / I.
angular_velocity_from_rotational_kinetic_energy: Computes angular velocity from rotational kinetic energy using ω = sqrt(2KE / I).
angular_velocity_from_tangential_speed: Computes angular velocity from tangential speed using ω = v / r.
centripetal_acceleration_from_angular_velocity: Computes centripetal acceleration using a_c = ω²r.
centripetal_acceleration_from_tangential_speed: Computes centripetal acceleration using a_c = v² / r.
degrees_from_radians: Converts radians to degrees.
final_angular_velocity: Computes final angular velocity using ω_final = ω_initial + αt.
final_angular_velocity_from_displacement: Computes final angular velocity using ω_final = sqrt(ω_initial² + 2αθ).
final_angular_velocity_squared: Computes squared final angular velocity using ω_final² = ω_initial² + 2αθ.
hollow_sphere_moment_of_inertia: Computes hollow-sphere moment of inertia using I = (2 / 3)mr².
point_mass_moment_of_inertia: Computes point-mass moment of inertia using I = mr².
radians_from_degrees: Converts degrees to radians.
radians_from_revolutions: Converts revolutions to radians.
revolutions_from_radians: Converts radians to revolutions.
rod_moment_of_inertia_about_center: Computes rod moment of inertia about its center using I = (1 / 12)mL².
rod_moment_of_inertia_about_end: Computes rod moment of inertia about one end using I = (1 / 3)mL².
rotational_kinetic_energy: Computes rotational kinetic energy using KE_rot = 0.5 * I * ω².
solid_disk_moment_of_inertia: Computes solid-disk moment of inertia using I = 0.5mr².
solid_sphere_moment_of_inertia: Computes solid-sphere moment of inertia using I = (2 / 5)mr².
tangential_acceleration: Computes tangential acceleration using a_t = αr.
tangential_speed: Computes tangential speed using v = ωr.
thin_ring_moment_of_inertia: Computes thin-ring moment of inertia using I = mr².