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FBI Mnemonics
The various FBI mnemonics (for electric motors) show the direction of the force on a conductor carrying a current in a magnetic field as predicted by Fleming's left hand rule for motors and Faraday's law of induction. Other mnemonics exist that use a right hand rule for predicting resulting motion from a preexisting current and field. Configuration, using the left hand 'FBI' The left hand is held with the thumb, first finger and second finger mutually at right angles. * The Thumb represents F - Thrust (or resulting Motion). * The First finger represents B - Field. * The Second finger represents I or V - Current (in the classical direction, from positive to negative). Configuration, using the right hand Other sources use the right hand to predict force, though the fingers used vary: 'FIB' * Thumb = F ("thrust") * Index finger = I or V * Middle finger (" Birdie") = B 'IBF' In this alternative, some versions recommend not extending the middle finger, but instead imagining ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Second Finger
The ''first finger'' is an ambiguous term in the English language due to two competing finger numbering systems that can be used. It might refer to either the thumb or the index finger, depending on the context. Consequently, also the terms ''second finger'', ''third finger'' and ''fourth finger'' depend on the numbering system used in the context. Instead, the ''fifth finger'' will exclusively refer to the pinky, (also called the ''little'' finger), since the term is only used in the five-finger system. Finger numbering systems The ordinal numbers of the fingers of the human hand are numbered ambiguously in the English language. This is due to two competing finger numbering systems that can be used. For instance, the first finger might refer to either the thumb or the index finger, depending on the context. Five-finger system In the ''five-finger system'', the ''first finger'' refers to the thumb (or first digit); usually this system is used in a medical context, or in a musical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Right Hand Grip Rule
In mathematics and physics, the right-hand rule is a convention and a mnemonic, utilized to define the orientation of axes in three-dimensional space and to determine the direction of the cross product of two vectors, as well as to establish the direction of the force on a current-carrying conductor in a magnetic field. The various right- and left-hand rules arise from the fact that the three axes of three-dimensional space have two possible orientations. This can be seen by holding your hands together with palms up and fingers curled. If the curl of the fingers represents a movement from the first or x-axis to the second or y-axis, then the third or z-axis can point along either right thumb or left thumb. History The right-hand rule dates back to the 19th century when it was implemented as a way for identifying the positive direction of coordinate axes in three dimensions. William Rowan Hamilton, recognized for his development of quaternions, a mathematical system for rep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Finger
The middle finger, long finger, second finger, third finger, toll finger or tall man is the third digit of the human hand, typically located between the index finger and the ring finger. It is typically the longest digit. In anatomy, it is also called ''the third finger'', ''digitus medius'', ''digitus tertius'' or ''digitus III''. Overview In Western countries, The finger, extending the middle finger (either by itself, or along with the index finger in the United Kingdom: see V sign) is an offensive and obscene gesture, widely recognized as a form of insult, due to its resemblance of an Erection, erect penis. It is known, colloquially, as "flipping the bird", "flipping (someone) off", or "giving (someone) the finger". The middle finger is often used for finger snapping together with the thumb. See also * Finger numbering * Galileo's middle finger References External links * Fingers Hand gestures {{Anatomy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Index Finger
The index finger (also referred to as forefinger, first finger, second finger, pointer finger, trigger finger, digitus secundus, digitus II, and many other terms) is the second digit of a human hand. It is located between the thumb and the middle finger. It is usually the most dextrous and sensitive digit of the hand, though not the longest. It is shorter than the middle finger, and may be shorter or longer than the ring finger (see digit ratio). Anatomy " Index finger" literally means "pointing finger", from the same Latin source as '' indicate;'' its anatomical names are "index finger" and "second digit". The index finger has three phalanges. It does not contain any muscles, but is controlled by muscles in the hand by attachments of tendons to the bones. Uses A lone index finger held vertically is often used to represent the number 1 (but finger counting differs across cultures), or when held up or moved side to side (finger-wagging), it can be an admonitory ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Finger (gesture)
"The finger", or the middle finger (as in giving someone the (middle) finger, flipping the bird or flipping someone off) is an obscene hand gesture. The gesture communicates moderate to extreme contempt, and is roughly equivalent in meaning to "fuck you", "shove it up your ass/arse", "up yours", or "go fuck yourself". It is performed by showing the back of a hand that has only the middle finger extended upwards, though in some locales, the thumb is extended. Extending the finger is considered a symbol of contempt in several cultures, especially in the Western world. Many cultures use similar gestures to display their disrespect, although others use it to express pointing without intentional disrespect. The gesture is usually used to express contempt but can also be used humorously or playfully. The gesture dates back to ancient Greece and it was also used in ancient Rome. Historically, it represented a phallus. In the early 1800s, it gained increasing recognition as a sign ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Negative Number
In mathematics, a negative number is the opposite (mathematics), opposite of a positive real number. Equivalently, a negative number is a real number that is inequality (mathematics), less than 0, zero. Negative numbers are often used to represent the Magnitude (mathematics), magnitude of a loss or deficiency. A debt that is owed may be thought of as a negative asset. If a quantity, such as the charge on an electron, may have either of two opposite senses, then one may choose to distinguish between those senses—perhaps arbitrarily—as ''positive'' and ''negative''. Negative numbers are used to describe values on a scale that goes below zero, such as the Celsius and Fahrenheit scales for temperature. The laws of arithmetic for negative numbers ensure that the common-sense idea of an opposite is reflected in arithmetic. For example, −(−3) = 3 because the opposite of an opposite is the original value. Negative numbers are usually written with a Plus and minus signs, minus sig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Positive Number
In mathematics, the sign of a real number is its property of being either positive, negative, or 0. Depending on local conventions, zero may be considered as having its own unique sign, having no sign, or having both positive and negative sign. In some contexts, it makes sense to distinguish between a positive and a negative zero. In mathematics and physics, the phrase "change of sign" is associated with exchanging an object for its additive inverse (multiplication with −1, negation), an operation which is not restricted to real numbers. It applies among other objects to vectors, matrices, and complex numbers, which are not prescribed to be only either positive, negative, or zero. The word "sign" is also often used to indicate binary aspects of mathematical or scientific objects, such as odd and even ( sign of a permutation), sense of orientation or rotation ( cw/ccw), one sided limits, and other concepts described in below. Sign of a number Numbers from various number ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Right Angles
In geometry and trigonometry, a right angle is an angle of exactly 90 degrees or radians corresponding to a quarter turn. If a ray is placed so that its endpoint is on a line and the adjacent angles are equal, then they are right angles. The term is a calque of Latin ''angulus rectus''; here ''rectus'' means "upright", referring to the vertical perpendicular to a horizontal base line. Closely related and important geometrical concepts are perpendicular lines, meaning lines that form right angles at their point of intersection, and orthogonality, which is the property of forming right angles, usually applied to vectors. The presence of a right angle in a triangle is the defining factor for right triangles, making the right angle basic to trigonometry. Etymology The meaning of ''right'' in ''right angle'' possibly refers to the Latin adjective ''rectus'' 'erect, straight, upright, perpendicular'. A Greek equivalent is ''orthos'' 'straight; perpendicular' (see orthogon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
First Finger
The ''first finger'' is an ambiguous term in the English language due to two competing finger numbering systems that can be used. It might refer to either the thumb or the index finger, depending on the context. Consequently, also the terms ''second finger'', ''third finger'' and ''fourth finger'' depend on the numbering system used in the context. Instead, the ''fifth finger'' will exclusively refer to the pinky, (also called the ''little'' finger), since the term is only used in the five-finger system. Finger numbering systems The ordinal numbers of the fingers of the human hand are numbered ambiguously in the English language. This is due to two competing finger numbering systems that can be used. For instance, the first finger might refer to either the thumb or the index finger, depending on the context. Five-finger system In the ''five-finger system'', the ''first finger'' refers to the thumb (or first digit); usually this system is used in a medical context, or in a musical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
