Pair of pulleys attached to usually parallel shafts and connected by an encircling flexible belt (band) that can serve to transmit and modify rotary motion from one shaft to the other. Most belt drives consist of flat leather, rubber, or fabric belts running on cylindrical pulleys or of belts with a V-shaped cross section running on grooved pulleys. Another type of belt, used on some internal-combustion engines for connecting the crankshaft and camshafts, is the toothed (or timing) belt, a flat belt with evenly spaced transverse teeth that fit in matching grooves on the periphery of the pulley.
Learn more about belt drive with a free trial on Britannica.com.
In psychology, an urgent need pressing for satisfaction, usually rooted in some physiological deficiency or imbalance (e.g., hunger and thirst) and impelling the organism to action. Psychologists distinguish between drives that are innate and directly related to basic physiological needs (e.g., food, air, and water) and drives that are learned (e.g., drug addiction). Among the other drives psychologists have identified are achievement, affection, affiliation, exploration, manipulation, maternity, pain avoidance, sex, and sleep.
Learn more about drive with a free trial on Britannica.com.
A drive-by shooting (or drive-by for short) is a form of hit-and-run tactic, a personal attack carried out by an individual or individuals from a moving or momentarily stopped vehicle. It often results in the shooting of innocent bystanders or a certain target. The objective is to overwhelm the target by a sudden, massive amount of firepower without attention to accuracy.
Some of the first gun control laws were passed to control assailants who would ride up to their targets on horseback, shoot them with wheellock pistols and then ride off before they could be apprehended.
For a time in the 70's the German special operations unit GSG 9 trained some of its operators in the "art" of the drive-by shooting so as to be able to better protect those in its charge.
An early example is found in the game Quarantine, where the player could aim an UZI out the side window.
The Grand Theft Auto series of video games allows the player to aim his or her sub-machine gun out of the window of his vehicle to shoot.
In Grand Theft Auto: San Andreas, there is a mission in which the player has to follow a fellow gang member on a bike while a gang is in a car behind and shooting at the protagonist. In Grand Theft Auto: Vice City Stories and Saints Row, the player can recruit various gang members to shoot out of the car against his enemies who include police and various opposing gangs.
The game Mafia: The City of Lost Heaven enables the player to use the mouse for more precise aiming during drive-by shootings. The camera moves with the mouse, requiring the player to concentrate both on the target and direction on the road at once. This style was also used in the Xbox 360 games Saint's Row and Grand Theft Auto IV.