Search results
Results from the WOW.Com Content Network
A 'gradual' deceleration has a time from onset to nadir of 30 seconds or more. Early decelerations begin and end at approximately the same time as contractions, and the low point of the fetal heart rate occurs at the peak of the contraction. [7] Late decelerations: a result of placental insufficiency, which can result in fetal distress ...
The deceleration parameter in cosmology is a dimensionless measure of the cosmic acceleration of the expansion of space in a Friedmann–Lemaître–Robertson–Walker universe. It is defined by: q = d e f − a ¨ a a ˙ 2 {\displaystyle q\ {\stackrel {\mathrm {def} }{=}}\ -{\frac {{\ddot {a}}a}{{\dot {a}}^{2}}}} where a {\displaystyle a} is ...
If the speed of the vehicle decreases, this is an acceleration in the opposite direction of the velocity vector (mathematically a negative, if the movement is unidimensional and the velocity is positive), sometimes called deceleration [4] [5] or retardation, and passengers experience the reaction to deceleration as an inertial force pushing ...
The early deceleration provided by reverse thrust can reduce landing roll by a quarter or more. [5] Regulations dictate, however, that an aircraft must be able to land on a runway without the use of thrust reversal in order to be certified to land there as part of scheduled airline service.
An early implementation of the concept was the Phantom bicycle in the early 1870s promoted as a safer alternative to the penny-farthing. [61] This design allows for simple front-wheel drive and current implementations appear to be quite stable, even rideable no-hands, as many photographs illustrate.
Target-type thrust reversal (also called bucket thrust reversal or clamshell thrust reversal [1]) is a deceleration method when an aircraft lands. Like other types of thrust reversals, it temporarily diverts the engine exhaust forward to provide deceleration. This type of thrust-reverser is suitable for engines of 3,000 lbf (13 kN) or greater ...
A crash test illustrates how a crumple zone absorbs energy from an impact. Road Maintenance Truck Impact Attenuator, Auckland, New Zealand Extent of the crumple zones (blue) and the driver's safety cell (red) of an E217 series train The crumple zone on the front of these cars absorbed the impact of an offset head-on collision.
The deceleration due to drag that a projectile with mass m, velocity v, and diameter d will experience is proportional to 1/BC, 1/m, v² and d². The BC gives the ratio of ballistic efficiency compared to the standard G1 projectile, which is a fictitious projectile with a flat base, a length of 3.28 calibers/diameters, and a 2 calibers ...