This formula supplies an easy method to find the angle between two planes ( or curved surfaces ) from their normal vectors and between skew lines from their vector equations.

Although the Cirth were later largely replaced by the Tengwar ( which were enhanced and brought by Fëanor ), they were adopted by Dwarves to write down their Khuzdul language ( Angerthas Moria and Angerthas Erebor ) because their straight lines were better suited to carving than the curved strokes of the Tengwar.

In modern parlance, their paths are geodesics, straight world lines in curved spacetime.

Translated into the language of spacetime: the straight time-like lines that define a gravity-free inertial frame are deformed to lines that are curved relative to each other, suggesting that the inclusion of gravity necessitates a change in spacetime geometry.

The classic example is conchoidal fracture, like that of quartz ; rounded surfaces are created, which are marked by smooth curved lines.

The diagrams do not imply that the particles are moving in straight or curved lines.

alt = Photo showing irregular black, red, and yellow areas on curved surface with thin, curved red lines projecting upwards from the surface.

: Simple or compound shape outlines are drawn with curved or straight lines that can be filled in, outlined, or used as a clipping path.

The grid lines do not represent the curvature of space but instead the coordinate system imposed on the curved spacetime, which would be regular grid | rectilinear in a flat spacetime.

Straight lines represent straight fingers ( these may be at an angle to indicate that they are not in line with the palm ; if they point toward or away from the signer, they have a diamond shape at the tip ); curved lines for curved ( cupped ) fingers ; hooked lines for hooked fingers ; right-angle lines, for fingers bent at only one joint ; and crossed lines, for crossed fingers, as shown in the chart at right.

Bonding diagram of diborane ( B < sub > 2 </ sub > H < sub > 6 </ sub >) showing with curved lines a pair of three-center two-electron bond s, each of which consists of a pair of electrons bonding three atoms, two boron atoms and a hydrogen atom in the middle.

White lines do not represent the curvature of space but instead represent the coordinate system imposed on the curved spacetime, which would be regular grid | rectilinear in a flat spacetime.

Although the relation between vapor pressure and temperature is non-linear, the chart uses a logarithmic vertical axis to produce slightly curved lines, so one chart can graph many liquids.

Menelaus of Alexandria ( c. 70 – 140 CE ) was a Greek mathematician and astronomer, the first to recognize geodesics on a curved surface as natural analogs of straight lines.

The two curved green tubes represent spline ( mathematics ) | spline fits to the polypeptide backbone.

This appearance may be recalled in the representation of Tigranes the Great, an Armenian king who is depicted on coins with a crown that features, according to V. G. Gurzadyan and R. Vardanyan, " a star with a curved tail may represent the passage of Halley's Comet in 87 BCE.

Whether the medieval instruments in fact represent forms of cornett is impossible to prove, but a number of extant 16th-century Italian curved cornetts that end in a beast ’ s head might be considered supporting evidence.

A recent ABC News article on May 19, 2004 noted that according to the Armenian and Italian researchers the " symbol on his crown that features a star with a curved tail may represent the passage of Halley's Comet in 87 BC.

The serekh on each side are flanked by a pair of bovine heads with highly curved horns, thought to represent the cow goddess Bat, who was the patron deity of the seventh nome of Upper Egypt and was also the deification of the cosmos and the Milky Way within Egyptian mythology during the pre-dynastic and Old Kingdom periods of Ancient Egyptian history.

The ship ’ s hull appears to emerge from two large buildings that feature curved, flowing roofs that were designed to represent ocean swells.

Costing £ 36 million, they stand in a line overlooking Huron Basin from the waterside of Pier 9 ( North Wharf ), their curved frontages designed to represent sails.

The original design was intended to represent the hand of God holding a jewel, with the curved corridors as the fingers, the straight corridors as his thumb, and a small chapel as the jewel.

Historians tell us that the curved shapes which represent bottoms are actually supposed to represent ocean waves, but gamblers prefer to call them bottoms and now the name has stuck.

This direct relationship between curved streamlines and pressure differences was derived from Newton's second law by Leonard Euler in 1754:

Another relationship involves the distance s along the curved surface of the Earth to the horizon ; with γ in radians,

They theorized that by mounting the axles at opposing angles, the wheels would go in a straight line when they were at the top of the arc and that when the wheels slid to either end of the arc, they would have a curved relationship that would result in a turn.

This relationship does not hold for curved spaces.

This meant, concretely, that the patient could not read at all without making writing-like movements of the head or body, became easily confused by `` hasher marks '' inserted between hand-written words and thus confused the mark for one of the letters, and could recognize a simple straight line or a curved one only by tracing it.

The area between the east and west coast highlands, which north of 17 ° N is mainly desert, is divided into separate basins by other bands of high ground, one of which runs nearly centrally through North Africa in a line corresponding roughly with the curved axis of the continent as a whole.

However, when a magnetic field with a perpendicular component is applied, their paths between collisions are curved so that moving charges accumulate on one face of the material.

A harmonica holder clamps the harmonica between two metal brackets, which are attached to a curved loop of metal that rests on the shoulders.

The game was played with a wooden curved bat ( called Colf or Kolf ) and a ball made of wood or leather between two poles or simply convenient nearby landmarks, with the object hitting the chosen point with the least number of strokes.

Einstein ’ s general theory modifies the distinction between nominally " inertial " and " noninertial " effects by replacing special relativity's " flat " Euclidean geometry with a curved metric.

Step height from platform to train is up to, and there can be a large gap between the train and curved platforms.

Differential characteristics between llamas and alpacas include the llama's larger size, longer head, and curved ears.

In architecture, a spandrel is a curved area of masonry which exists between arches supporting a dome.

There are four or five accepted and cognate meanings of spandrel in architectural and art history, mostly relating to the space between a curved figure and a rectangular boundary-such as the space between the curve of an arch and a rectilinear bounding moulding, or the wallspace bounded by adjacent arches in an arcade and the stringcourse or moulding above them, or the space between the central medallion of a carpet and its rectangular corners, or the space between the circular face of a clock and the corners of the square revealed by its hood.

It is lightly curved, creating a large hollow between the plate and the soundboard.

When strained, the zone between the straight and curved regions are subject to strong bending, shear, and longitudinal stresses.

Entopic graphomania is a surrealist and automatic method of drawing in which dots are made at the sites of impurities in a blank sheet of paper, and lines are then made between the dots ; these can be either " curved lines ... or straight lines .".

A corona discharge occurs between a highly curved electrode, for example the tip of a needle or a small diameter wire, and an electrode of low curvature such as a flat plate.

Light rays bend at the interface between two dissimilar media and may be curved in a medium in which the refractive index changes.

The shortest path between two points in a curved space can be found by writing the equation for the length of a curve ( a function f from an open interval of R to the manifold ), and then minimizing this length using the calculus of variations.

Even light itself does not have a " velocity " of c in this sense ; the total velocity of any object can be expressed as the sum where is the recession velocity due to the expansion of the universe ( the velocity given by Hubble's law ) and is the " peculiar velocity " measured by local observers ( with and, the dots indicating a first derivative ), so for light is equal to c (- c if the light is emitted towards our position at the origin and + c if emitted away from us ) but the total velocity is generally different than c .( Davis and Lineweaver 2003, p. 19 ) Even in special relativity the coordinate speed of light is only guaranteed to be c in an inertial frame, in a non-inertial frame the coordinate speed may be different than c ; in general relativity no coordinate system on a large region of curved spacetime is " inertial ", but in the local neighborhood of any point in curved spacetime we can define a " local inertial frame " and the local speed of light will be c in this frame, with massive objects such as stars and galaxies always having a local speed smaller than c. The cosmological definitions used to define the velocities of distant objects are coordinate-dependent-there is no general coordinate-independent definition of velocity between distant objects in general relativity ( Baez and Bunn, 2006 ).