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:
“The young ... look into visages dull-eyed, long-toothed, wattle-necked, and chop-fallen, something they have never been and which they cannot imagine ever being.... If it occurs to a young person, looking at us, that this is the direction in which he himself travels, how can he forgive, let alone bear the sight of, us, who constantly bring him the bad news of our own faces, bitter signposts pointing to his own destination?”
—Jessamyn West (19021984)
“Today everything is different. I cant even get decent food. Right after I got here I ordered some spaghetti with marinara sauce and I got egg noodles and catsup. Im an average nobody, I get to live the rest of my life like a schnook.”
—Nicholas Pileggi, U.S. screenwriter, and Martin Scorsese. Henry Hill (Ray Liotta)
“I saw a guide-post surmounted by a pair of moose horns.... They are sometimes used for ornamental hat-trees, together with deers horns, in front entries; but ... I trust that I shall have a better excuse for killing a moose than that I may hang my hat on his horns.”
—Henry David Thoreau (18171862)
“Have we any control over being born?, my friend asked in despair. No, the job is done for us while were 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 dont remember, my friend claimed. No need to, I said: what need have us free-loaders for any special alertness? Were done for.”
—Marvin Cohen, U.S. author and humorist. The Self-Devoted Friend, New Directions (1967)