Direction Associated With An Ordered Pair of Directions
One form of the right-hand rule is used in situations in which an ordered operation must be performed on two vectors a and b that has a result which is a vector c perpendicular to both a and b. The most common example is the vector cross product. The right-hand rule imposes the following procedure for choosing one of the two directions.
- With the thumb, index, and middle fingers at right angles to each other (with the index finger pointed straight), the middle finger points in the direction of c when the thumb represents a and the index finger represents b.
Other (equivalent) finger assignments are possible. For example, the first (index) finger can represent a, the first vector in the product; the second (middle) finger, b, the second vector; and the thumb, c, the product.
Read more about this topic: Right-hand Rule
Famous quotes containing the words direction, ordered, pair and/or directions:
“It is not easy to construct by mere scientific synthesis a foolproof system which will lead our children in a desired direction and avoid an undesirable one. Obviously, good can come only from a continuing interplay between that which we, as students, are gradually learning and that which we believe in, as people.”
—Erik H. Erikson (20th century)
“But one sound always rose above the clamor of busy life and, no matter how much of a tintinnabulation, was never confused and, for a moment lifted everything into an ordered sphere: that of the bells.”
—Johan Huizinga (1872–1945)
“With two sons born eighteen months apart, I operated mainly on automatic pilot through the ceaseless activity of their early childhood. I remember opening the refrigerator late one night and finding a roll of aluminum foil next to a pair of small red tennies. Certain that I was responsible for the refrigerated shoes, I quickly closed the door and ran upstairs to make sure I had put the babies in their cribs instead of the linen closet.”
—Mary Kay Blakely (20th century)
““Have we any control over being born?,” my friend asked in despair. “No, the job is done for us while we’re sleeping, so to speak, and when we wake up everything is all set. We merely appear, like an ornate celebrity wheeled out in a wheelchair.” “I don’t remember,” my friend claimed. “No need to,” I said: “what need have us free-loaders for any special alertness? We’re done for.””
—Marvin Cohen, U.S. author and humorist. The Self-Devoted Friend, New Directions (1967)