Inertia Law = Xogta qaynuunka nuuxsi wax-negaadsan
Acceleration = Xowli
Response Act = Qaynuunka falka iyo falcelinta
Theory of Relativity = Fikriga isudhiganka
Quantum Theory = Fikriga imisada ama meeqada
Mass = Jir
Energy = Tabarta
Relative = Hadba Rogmada
Electromagnetic wavelengths = Dhererka hirarka ku danabeysan birlabta
“In geometry, a surface S is ruled (also called a scroll) if through every point of S there is a straight line that lies on S. The most familiar examples (illustrated here in three-dimensional Euclidean space) are the plane and the curved surface of acylinder or cone. Other examples are a conical surface with elliptical directrix, the right conoid, the helicoid, and the tangent developable of a smooth curve in space.” - wikipedia
A ruled surface can always be described (at least locally) as the set of points swept by a moving straight line.
Origami, the art of paper folding, can be interpreted as an intriguing geometrical model. Folds represent lines, and intersections of folds, points. Now, to model origami, we need to know which new folds one can make from a given configuration. The most natural model uses the axioms of Huzita-Hatori-Justin, describing the operations that can be made when folding a piece of paper.
Humiaki Huzita discovered and reported the first six axioms in 1991. The seventh independent construction was discovered by Koshiro Hatori in 2001. Jacques Justin, however, already published the complete system with seven axioms in 1989, but his work remained unnoticed.
Axiom 1: one can fold a line through two given points.
Axiom 2: one can fold a given point onto another given point.
Axiom 3: one can fold a given line onto another given line.
Axiom 4: one can fold a given line onto itself, while folding through a given point.
Axiom 5: one can fold a given point onto a given line, while folding through a given point.
Axiom 6: one can fold two given points on two given lines.
Axiom 7: one can fold a given line onto itself, while folding a given point onto another given line.
The first two axioms don’t seem that exciting, but they are needed for basic constructions. Axiom 3 states the construction of bissectrices, axiom 4 the construction of perpendiculars. Axiom 5, interestingly, provides a method for solving quadratic equations by origami; the new fold is in fact a tangent line to a parabola (with the given point and fold as focus and directrix, respectively) through a given point. Axiom 6 even allows us to solve cubic equations, which is in general not possible using only straightedge and compass!