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Return to Terminology
W
- Warhead
- That portion of a rocket. guided missile or torpedo containing
the destructive load which the vehicle is to deliver.
- Warning Signal
- A visual or audible signal that is used for warning personnel
in the vicinity of the blast area of the impending explosion.
- Water
- Water, odorless, tasteless, transparent liquid that is
colorless in small amounts but exhibits a bluish tinge in large quantities. It is the most
abundant liquid on earth. In solid form (ice) and liquid form it covers about 70% of the
earth's surface. Chemically, water is a compound of hydrogen and oxygen whose formula is
H2O. The two H—O bonds form an angle of about 105°—an arrangement that results
in a polar molecule, because there is a net negative charge toward the oxygen end (the
apex) of the V-shaped molecule and a net positive charge at the hydrogen ends.
Consequently, each oxygen atom is able to attract two nearby hydrogen atoms of two other
water molecules. These hydrogen bondings keep water liquid at ordinary temperatures.
Because water is a polar compound, it is a good solvent. Because of the hydrogen bondings
between molecules, the latent heats of fusion and of evaporation and the Heat Capacity of
water are all unusually high. For these reasons water serves both as a heat-transfer
medium (e.g., ice for cooling and steam for heating) and as a temperature regulator (the
water in lakes and oceans helps regulate the climate). Water is chemically active,
reacting with certain metals and metal oxides to form bases, and with certain oxides of
nonmetals to form acids. Although completely pure water is a poor conductor of
electricity, it is a much better conductor than most pure liquids because of its
self-ionization, i.e., the ability of two water molecules to react to form a hydroxyl ion
(OH-) and a hydronium ion (H3O+).
- Water Gel
- An explosive material containing substantial portions of
water, oxidizers, and fuel, plus a cross-linking agent.
- Watt
- A unit of electrical power equal to 1 joule/sec.
- Wave
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Wave in physics, the transfer of
Energy by some form of regular vibration, or oscillatory motion, either of some material
medium ( Sound) or by the variation of intensity of the field
vectors of an electromagnetic field ( Electromagnetic
Radiation). In longitudinal, or compressional, waves the vibration is in the same
direction as the transfer of energy; in transverse waves the vibration is at right angles
to the transfer of energy. The amplitude of a wave is its maximum displacement. The
distance between successive crests or successive troughs is the wavelength l of a wave.
One full wavelength of a wave represents one complete cycle, that is, one complete
vibration in each direction. All waves are referenced to an imaginary synchronous motion
in a circle; thus one complete cycle is divided into 360 degrees. The phase is that part
of the cycle, expressed in degrees, that is completed at a certain time. The various phase
relationships between combining waves determine the type of interference that takes place.
The frequency n of a wave is equal to the number of crests (or troughs) that pass a given
fixed point per unit of time. The period T of a wave is the time lapse between the passage
of successive crests (or troughs). The speed v of a wave is determined by its wavelength
and its frequency according to the equation v = ln. Because the frequency is inversely
related to the period T, this equation also takes the form v = l/T. |
- Wavefront
- Surface which is the locus of all molecules having motion in
identical phase in a propagating wave.
- Weather-Resistant
- Construction designed to offer reasonable protection against
weather.
- Web, Web Size, Web Thickness
- 1) Alternate terms describing the minimum distance between any
two specified burning surfaces of a propellant grain.
- 2) Terms used in describing portions of structural
“I” beams and “H” beams.
- Web Range
- Tolerance of web thickness to allow for manufacturing
limitation.
- Weight
- The force with which an earth-bound body is attracted toward
the earth. Weight, a measure, commonly expressed in pounds or grams, of the force of
gravity on a body ( Gravitation), which is more correctly
measured in newtons. Because the weights of different bodies at the same location are
proportional to their masses, weight is often used as a measure of Mass.
Unlike the mass, the weight of a body depends on its location in the gravitational field
of the earth or of some other astronomical body.
- Weights And Measures
- Weights and measures, units and standards for expressing the
amount of some quantity, such as length, capacity, or weight; the science of measurement
standards and methods is known as metrology. Crude systems of weights and measures
probably date from prehistoric times. Early units were commonly based on body measurements
and on plant seeds or other agricultural objects. As civilization progressed,
technological and commercial requirements led to increased standardization. Units were
usually fixed by edict of local or national rulers and were subdivided and multiplied or
otherwise arranged into systems of measurement. Today the chief systems are the English
Units Of Measurement and the Metric System. The United
States is one of the few countries still using the former system.
- Weight Strength
- The energy of an explosive material per unit of weight
expressed as a percentage of the energy per unit of weight of a specified explosive
standard.
- White Phosphorous (WP)
- Yellow waxy solid which ignites spontaneously when exposed to
air. It is used as a filling for various projectiles as a smoke-producing agent and has an
incendiary effect. White phosphorous may be mixed with a xylene solution of synthetic rubber to form plasticized white phosphorous.
- Window
- A type of confusion reflector consisting essentially of metal
foil ribbon, but sometimes metalized on one side only. Also known as "chaff."
Similar to, but shorter in length than rope. Rope.
- Windshield
- Ballistic Cap.
- Work
- Work, in physics, transfer of Energy by a force acting against
a resistance or a body and resulting in displacement. Work W has a magnitude equal to the
scalar product ( Vector) of the force F and the distance d of
the resulting movement; thus W = Fd cos ;gu, where;gu is the angle between the directions
of the force and the movement. The foot-pound (English Units of
Measurement), the erg (cgs system), and the joule (mks system) are the units of
work or energy expended, respectively, by a 1-lb force acting through a distance of 1 ft,
by a 1-dyne force through 1 cm, and by a 1-newton force through 1 m. One foot-pound equals
1.356 joules; 1 erg equals 10-7 joules.
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