Relative direction

The most common relative directions are left, right, forward(s), backward(s), up, and down. No absolute direction corresponds to any of the relative directions. This is a consequence of the translational invariance of the laws of physics: nature, loosely speaking, behaves the same no matter what direction one moves. As demonstrated by the Michelson-Morley null result, there is no absolute inertial frame of reference. There are definite relationships between the relative directions, however. Left and right, forward and backward, and up and down are three pairs of complementary directions, each pair orthogonal to both of the others. Relative directions are also known as egocentric coordinates.

Traditions and conventions

Since definitions of left and right based on the geometry of the natural environment are unwieldy, in practice, the meaning of relative direction words is conveyed through tradition, acculturation, education, and direct reference. One common definition of up and down uses gravity and the planet Earth as a frame of reference. Since there is a very noticeable force of gravity acting between the Earth and any other nearby object, down is defined as that direction which an object moves in reference to the Earth when the object is allowed to fall freely. Up is then defined as the opposite direction of down. Another common definition uses a human body, standing upright, as a frame of reference. In that case, up is defined as the direction from feet to head, perpendicular to the surface of the Earth. In most cases, up is a directionally oriented position generally opposite to that of the pull of gravity.

Spindle (automobile)

In an automobile, the spindle is a part of the suspension system that carries the hub for the wheel and attaches to the upper and lower control arms. The spindle is referred to as an Upright in UK-built vehicles and in areas dominated by cars designed for the UK, like Australia, New Zealand etc.

Design

There are several considerations when designing an upright. Loads and forces need to be considered. Vertical and horizontal forces greater than those due to 5 times the acceleration of gravity, that is, about 50 meters per second per second, are sometimes considered desirable.

Non-driven wheel

The main forces on a non-driven wheel are braking and turning forces.

Driven wheel

The forces on a driven wheel include forward and reverse propulsion as well as the braking and turning forces.

References

Pain (philosophy)

Philosophy of pain may be about suffering in general or more specifically about physical pain. The experience of pain is, due to its seeming universality, a very good portal through which to view various aspects of human life. Discussions in philosophy of mind concerning qualia has given rise to a body of knowledge called philosophy of pain, which is about pain in the narrow sense of physical pain, and which must be distinguished from philosophical works concerning pain in the broad sense of suffering. This article covers both topics.

Historical views of pain

Two near contemporaries in the 18th and 19th centuries, Jeremy Bentham and the Marquis de Sade had very different views on these matters. Bentham saw pain and pleasure as objective phenomena, and defined utilitarianism on that principle. However the Marquis de Sade offered a wholly different view - which is that pain itself has an ethics, and that pursuit of pain, or imposing it, may be as useful and just as pleasurable, and that this indeed is the purpose of the state - to indulge the desire to inflict pain in revenge, for instance, via the law (in his time most punishment was in fact the dealing out of pain). The 19th-century view in Europe was that Bentham's view had to be promoted, de Sade's (which it found painful) suppressed so intensely that it - as de Sade predicted - became a pleasure in itself to indulge. The Victorian culture is often cited as the best example of this hypocrisy.

Pain (Puff Daddy song)

"Pain" is a song on Puff Daddy's 1997 album No Way Out.

The song is about tragedies from Puff Daddy's life, including the murder of his father Melvin Combs in 1972, the New York City College Stampede of 1991 and the death of his label-mate and friend Notorious BIG in 1997.

The song features audio from Notorious BIG which was recorded before his death when the song was made.

There is a completely different song also entitled Pain on the follow-up album Forever.

King of da Ghetto

King of da Ghetto is the third solo album by southern rapper Z-Ro.

Track listing