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Safety Net
A safety net is a net to protect people from injury after falling from heights by limiting the distance they fall, and deflecting to dissipate the impact energy. The term also refers to devices for arresting falling or flying objects for the safety of people beyond or below the net. Safety nets are used in construction, building maintenance, entertainment, or other industries. Action of a safety net A safety net gives falling objects much more time to come to rest than hitting hard ground directly. In physical terms, this means more time for deceleration and kinetic energy transfer, resulting in a softer landing and much lower risk of damage. What kind of net to be used, depends upon many factors, (such as the factors that could determine force of the impact) such as falling objects's speed and mass. To encounter more force, a more total width of the net, is required. The minimum distance of the spot on net at which object impacted, and the edge of net (nearest edge), ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Under The Safety Net - Geograph
Under may refer to: * "Under" (Alex Hepburn song), 2013 * "Under" (Pleasure P song), 2009 *Bülent Ünder (born 1949), Turkish footballer *Cengiz Ünder (born 1997), Turkish footballer *Marie Under Marie Under ( – 25 September 1980) was one of the greatest Estonian poets. She was nominated for the Nobel Prize in Literature in 12 separate years. Early life Under was born in Reval (now Tallinn), Estonia to school teachers ... (1883–1980), Estonian poet * Under (restaurant), underwater Norwegian restaurant {{disambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Buffer Stop
A buffer stop, bumper, bumping post, bumper block or stopblock (US), is a device to prevent railway vehicles from going past the end of a physical section of track. The design of the buffer stop is dependent, in part, on the kind of couplings that the railway uses, since the coupling gear is the first part of the vehicle that the buffer stop touches. The term "buffer stop" is of British origin, since railways in Great Britain principally use buffer-and-screw couplings between vehicles. Types Several different types of buffer stop have been developed. They differ depending on the type of coupler used and on the intended application. * Buffer stops with anticlimbers. These are particularly important for passenger railway applications, because the anticlimbers reduce the likelihood of telescoping of the railroad cars during a head-on impact. * Buffer stops for a knuckle coupler or an SA3 coupler (centrally positioned between the two rails) * Buffer stops with traditional " ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terminal Velocity
Terminal velocity is the maximum velocity (speed) attainable by an object as it falls through a fluid ( air is the most common example). It occurs when the sum of the drag force (''Fd'') and the buoyancy is equal to the downward force of gravity (''FG'') acting on the object. Since the net force on the object is zero, the object has zero acceleration. In fluid dynamics an object is moving at its terminal velocity if its speed is constant due to the restraining force exerted by the fluid through which it is moving. As the speed of an object increases, so does the drag force acting on it, which also depends on the substance it is passing through (for example air or water). At some speed, the drag or force of resistance will equal the gravitational pull on the object (buoyancy is considered below). At this point the object stops accelerating and continues falling at a constant speed called the terminal velocity (also called settling velocity). An object moving downward faster t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brake
A brake is a mechanical device that inhibits motion by absorbing energy from a moving system. It is used for slowing or stopping a moving vehicle, wheel, axle, or to prevent its motion, most often accomplished by means of friction. Background Most brakes commonly use friction between two surfaces pressed together to convert the kinetic energy of the moving object into heat, though other methods of energy conversion may be employed. For example, regenerative braking converts much of the energy to electrical energy, which may be stored for later use. Other methods convert kinetic energy into potential energy in such stored forms as pressurized air or pressurized oil. Eddy current brakes use magnetic fields to convert kinetic energy into electric current in the brake disc, fin, or rail, which is converted into heat. Still other braking methods even transform kinetic energy into different forms, for example by transferring the energy to a rotating flywheel. Brakes are gene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Collision
In physics, a collision is any event in which two or more bodies exert forces on each other in a relatively short time. Although the most common use of the word ''collision'' refers to incidents in which two or more objects collide with great force, the scientific use of the term implies nothing about the magnitude of the force. Some examples of physical interactions that scientists would consider collisions are the following: * When an insect lands on a plant's leaf, its legs are said to collide with the leaf. * When a cat strides across a lawn, each contact that its paws make with the ground is considered a collision, as well as each brush of its fur against a blade of grass. * When a boxer throws a punch, their fist is said to collide with the opponents body. * When an astronomical object merges with a black hole, they are considered to collide. Some colloquial uses of the word collision are the following: * A traffic collision involves at least one automobile. * A mid-air ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Impulse (physics)
In classical mechanics, impulse (symbolized by or Imp) is the integral of a force, , over the time interval, , for which it acts. Since force is a vector quantity, impulse is also a vector quantity. Impulse applied to an object produces an equivalent vector change in its linear momentum, also in the resultant direction. The SI unit of impulse is the newton second (N⋅s), and the dimensionally equivalent unit of momentum is the kilogram meter per second (kg⋅m/s). The corresponding English engineering unit is the pound-second (lbf⋅s), and in the British Gravitational System, the unit is the slug-foot per second (slug⋅ft/s). A resultant force causes acceleration and a change in the velocity of the body for as long as it acts. A resultant force applied over a longer time, therefore, produces a bigger change in linear momentum than the same force applied briefly: the change in momentum is equal to the product of the average force and duration. Conversely, a small forc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jerk (physics)
In physics, jerk or jolt is the rate at which an object's acceleration changes with respect to time. It is a vector quantity (having both magnitude and direction). Jerk is most commonly denoted by the symbol and expressed in m/s3 (SI units) or standard gravity, standard gravities per second (''g''0/s). Expressions As a vector, jerk can be expressed as the first time derivative of acceleration, second derivative, second time derivative of velocity, and third derivative, third time derivative of position (vector), position: \mathbf j(t) = \frac = \frac = \frac where * is acceleration * is velocity * is position * is time Third-order differential equations of the form J\left(\overset, \ddot, \dot, x\right) = 0 are sometimes called ''jerk equations''. When converted to an equivalent system of three ordinary Differential equation#Ordinary differential equations, first-order Differential equation#Non-linear differential equations, non-linear differential equations, jerk equations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Impact (mechanics)
In mechanics, an impact is a high force or Shock (mechanics), shock applied over a short time period when two or more bodies Collision, collide. Such a force or acceleration usually has a greater effect than a lower force applied over a proportionally longer period. The effect depends critically on the relative velocity of the bodies to one another. At normal speeds, during a perfectly inelastic collision, an object struck by a projectile will Deformation (engineering), deform, and this deformation will absorb most or all of the force of the collision. Viewed from a conservation of energy perspective, the kinetic energy of the projectile is changed into heat and sound energy, as a result of the deformations and vibrations induced in the struck object. However, these deformations and vibrations cannot occur instantaneously. A high-velocity collision (an impact) does not provide sufficient time for these deformations and vibrations to occur. Thus, the struck material behaves as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shock (mechanics)
A mechanical or physical shock is a sudden acceleration caused, for example, by impact, drop, kick, earthquake, or explosion. Shock is a transient physical excitation. Shock describes matter subject to extreme rates of force with respect to time. Shock is a vector that has units of an acceleration (rate of change of velocity). The unit ''g'' (or g) represents multiples of the acceleration of gravity and is conventionally used. A shock pulse can be characterised by its peak acceleration, the duration, and the shape of the shock pulse (half sine, triangular, trapezoidal, etc.). The shock response spectrum is a method for further evaluating a mechanical shock. Shock measurement Shock measurement is of interest in several fields such as *Propagation of heel shock through a runner's body *Measure the magnitude of a shock need to cause damage to an item: fragility. *Measure shock attenuation through athletic flooring *Measuring the effectiveness of a shock absorber *Measuring the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cushioning
Package cushioning is used to protect items during shipment. Vibration and impact shock during shipment and loading/unloading are controlled by cushioning to reduce the chance of product damage. Cushioning is usually inside a shipping container such as a corrugated box. It is designed to absorb shock by crushing and deforming, and to dampen vibration, rather than transmitting the shock and vibration to the protected item. Depending on the specific situation, package cushioning is often between thick. Internal packaging materials are also used for functions other than cushioning, such as to immobilize the products in the box and lock them in place, or to fill a void. Design factors When designing packaging the choice of cushioning depends on many factors, including but not limited to: * effective protection of product from shock and vibration * resilience (whether it performs for multiple impacts) * resistance to creep – cushion deformation under static load * material costs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Damped Wave
Damping is an influence within or upon an oscillatory system that has the effect of reducing or preventing its oscillation. In physical systems, damping is produced by processes that dissipate the energy stored in the oscillation. Examples include viscous drag (a liquid's viscosity can hinder an oscillatory system, causing it to slow down; see viscous damping) in mechanical systems, resistance in electronic oscillators, and absorption and scattering of light in optical oscillators. Damping not based on energy loss can be important in other oscillating systems such as those that occur in biological systems and bikes (ex. Suspension (mechanics)). Not to be confused with friction, which is a dissipative force acting on a system. Friction can cause or be a factor of damping. The damping ratio is a dimensionless measure describing how oscillations in a system decay after a disturbance. Many systems exhibit oscillatory behavior when they are disturbed from their position of s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Damper (other)
A damper is a device that deadens, restrains, or depresses. It may refer to: Music * Damper pedal, a device that mutes musical tones, particularly in stringed instruments * A mute for various brass instruments Structure * Damper (flow), a mechanical device in a duct or chimney that regulates airflow * Stockbridge damper, used to suppress wind-induced vibrations on taut cables * Tuned mass damper, a device mounted in structures to prevent discomfort, damage or structural failure by vibration Other uses * Damper (food), a bread of the Australian Outback * Dashpot A dashpot, also known as a damper, is a mechanical device that resists motion via viscous friction. The resulting force is proportional to the velocity, but acts in the opposite direction, slowing the motion and absorbing energy. It is commonly us ..., a type of hydraulic or mechanical damper * Shock absorber (British or technical use: ''damper''), a mechanical device designed to dissipate kinetic energy * An item of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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