The dimensions of force are ma.s.s (M) * acceleration (L/(T^2)) = (M*L)/(T^2).

260 STANDARD ELECTRICAL DICTIONARY.

Force de Cheval. Horse power (French).

It is the French or metric horse power.

It is equal to: 542.496 Foot lbs. per second.

.9864 English Horse Power.

75.0 Kilogram-meters per second.

Force, Electro-magnetic.

The mechanical force of attraction or repulsion acting on the electro-magnetic unit of quant.i.ty. Its intensity varies with the square of the distance. It may also be defined as electric force in the electro-magnetic system.

Its dimensions are equal to mechanical force ((M*L)/(T^2)) divided by quant.i.ty ((M^.5)*(L^.5)) = ((M^.5)*(L^.5))/(T^2).

Force, Electrostatic.

The force by which electric matter or electrified surfaces attract or repel each other. It is also termed electric force (not good) and electro-motive intensity. It is the mechanical force acting upon a unit quant.i.ty of electricity. Its intensity varies with the square of the distance.

Its dimensions are therefore equal to (quant.i.ty * unity / (square of distance) Q. * 1 / (L^2) = ((M^.5) * (L^1.5) )/ T*1 / (L^2) = ((M^.5) * (L^.5)) / T These dimensions are also those of potential difference.

[Transcriber's Note: The image of the preceding paragraph is included for "clarity".]

The objection to the term electric force is that it may be applied also to electro-magnetic force, and hence be a source of confusion.

Forces, Parallelogram of.

The usual method of composing forces or resolving a force. The sides of a parallelogram of forces represent component forces and the diagonal represents the resultant. See Component--Resultant--Forces, Composition of--Forces, Resolution of.

Forces, Composition of.

When several forces act in a different direction upon a point they may be drawn or graphically represented as arrows or lines emanating from the point in the proper direction and of lengths proportional to the force they exercise. Any two can be treated as contiguous sides of a parallelogram and the parallelogram can be completed. Then its diagonal, called the resultant, will represent the combined action of the two forces, both as regards direction and intensity. This is the composition of two forces.

If more than two forces act upon the given point the resultant can be composed with any of the others and a new force developed. The new resultant can be combined with another force, and the process kept up, eliminating the components one by one until a final resultant of all is obtained. This will give the exact direction and intensity of the forces, however many or varied.

261 STANDARD ELECTRICAL DICTIONARY.

Forces, Resolution of.

The developing from a single force treated as a resultant, two other forces in any desired direction. The reverse of composition of forces.

(See Forces, Composition of--Forces, Parallelogram of--Components--Resultant.)

Force, Tubes of.

Aggregations of lines of force, either electrostatic or magnetic. They generally have a truncated, conical or pyramidal shape and are not hollow. Every cross-section contains the same number of lines. The name it will seem is not very expressive.

Force, Unit of.

The fundamental or C. G. S. unit or force is the dyne, q. v.

The British unit of force is the poundal (the force which will produce an acceleration of one foot per second in a ma.s.s of one pound). It is equal to about 10/322 pound. A force cannot be expressed accurately in weight units, because weight varies with the lat.i.tude.

Forming.

The process of producing secondary battery plates from lead plates by alternately pa.s.sing a charging current through the cell and then allowing it to discharge itself and repeating the operation. (See Battery, Secondary, Plant?'s.)

Foundation Ring.

In a dynamo armature the ring-shaped core on which Gramme ring armatures and other ring armatures are wound.

Fourth State of Matter.

Gas so rarefied that its molecules do not collide, or rarely do so; radiant matter, q. v.

[Transcriber's note: This term now refers to plasma, an ionized gas, which contains free electrons. The ions and electrons move somewhat independently making plasma electrically conductive. It responds strongly to electromagnetic fields.]

Frame.

In a dynamo the bed-piece is sometimes called the frame.

Franklin's Experiment.

Franklin proved the ident.i.ty of lightning and electricity by flying a kite in a thunder storm. The kite was of silk so as to endure the wetting. When the string became wet sparks could be taken from a key attached to its end. The main string was of hemp; at the lower end was a length of silk to insulate it. The key was attached near the end of and to the hemp string.

Franklin's Plate.

A simple form of condenser. It consists of a plate of gla.s.s coated on each side with tinfoil with a margin of about an inch of clear gla.s.s.

One coating may be grounded as indicated in the cut, and the plate charged like a Leyden jar. Or one side may be connected with one terminal, and the other with the other terminal of an influence machine and the pane will be thus charged.

Synonym--Fulminating Pane.

262 STANDARD ELECTRICAL DICTIONARY.

Fig. 174. FRANKLIN'S PLATE.

Franklin's Theory.

The single fluid theory, q. v., of electricity.

Frequency.

The number of double reversals or complete alternations per second in an alternating current.

Synonym--Periodicity.