# Resistances Sentence Examples

- The sizes of copper wire employed have weights of too, 150, 200 and 400 lb per statute mile, and have electrical
**resistances**(at 60° F.) of 8.782, 5.8 55, 4.39 1 and 2.195 standard ohms respectively. - In practice the
**resistances**r, r' are 9 Earth FIG. - The leakage through the insulator of the cable is compensated for by connecting high
**resistances**between different points of the strip conductor and the earth coating. - Faults or any other irregularity in the cable may be represented by putting
**resistances**of the proper kind into the artificial line. - Ann., 1890, 40, p. 56) employed an arrangement as follows: Four fine platinum or iron wires were joined in lozenge shape, and two sets of these R and S were connected up with two
**resistances**P and Q to form a bridge with a galvanometer G and battery B. - If the attack of a parasite is met by the formation of some substance in the protoplasm which is chemo- tactically repulsive to the invader, it may be totally incapable of penetrating the cell, even though equipped with a whole armoury of cytases, diastatic and other enzymes, and poisons which would easily overcome the more passive
**resistances**offered by mere cell-walls and cell-contents of other plants, the protoplasm of which forms bodies chemotactically attractive to the Fungus. - The relation between the b.h.p. and the torque on the driving-axle is 55 o B.H.P. =Tu., (9) It is usual with steam locomotives to regard the resistance R as including the frictional
**resistances**between the cylinders and the driving-axle, so that the rate at which energy is expended in moving the train is expressed either by the product RV, or by the value of the indicated horse-power, the relation between them being 55 0 I.H.P. =RV (Io) or in terms of the torque 55 0 I.H.P.X€=RVe=TW (II) The individual factors of the product RV may have any value consistent with equation (to) and with certain practical conditions, so that for a given value of the I.H.P. R must decrease if V increases. - The pull recorded on the diagram includes the
**resistances**due to acceleration and to the gradient on which the train is moving. - It is usual to subtract these
**resistances**from the observed pull, so as to obtain the draw-bar pull reduced to what it would be at a uniform speed on the level. - A side wind causes excessive flange friction on the leeward side of the train, and increases the tractive
**resistances**therefore very considerably, even though its velocity be relatively moderate. - Rate at which work is done against the
**resistances**given by the curves fig. - Per hour on a level straight road with the values of the
**resistances**assumed. - These considerations also indicate what a difficult matter it is to find the exact rate of working against the
**resistances**, because of the difficulty of securing conditions which eliminate the effect both of the gradient and of acceleration. - Secondly, it must be able to maintain the train at a given speed against the total
**resistances**of the level or up a gradient of given inclination. - The calibration of ammeters is best conducted by means of a series of standard low
**resistances**and of a potentio meter. - The strength of the current may also be regulated by introducing lengths of German silver or iron wire, carbon rod, or other inferior conductors in the path of the current, and a series of such
**resistances**should always be provided close to the tanks. - Several pieces of apparatus have been invented for comparing the magnetic quality of a sample with that of a standard iron rod by a zero method, such as is employed in the comparison of electrical
**resistances**by the Wheatstone bridge. - The effective number of turns in the coil surrounding the test rod can be varied by means of three dial switches (for hundreds, tens and units), which also introduce compensating
**resistances**as the number of effective turns in the coil is reduced, thus keeping the total resistance of the circuit constant. - For the purpose of measuring
**resistances**up to a few thousand ohms, the most convenient appliance is a Wheatstone's Bridge (q.v), but when the resistance of the conductor to be measured is several hundred thousand ohms, or if it is the resistance of a so-called insulator, such as the insulating covering of the copper wires employed for distributing electric current in houses and buildings for electric lighting, then the ohmmeter is more convenient. - In practical work, the low
**resistances**take the form of certain strips of metal which have on them two pairs of terminals, one termed " current terminals," and the other " potential terminals." - It appears then that this sum is a measure of the total capacity for doing work against extraneous
**resistances**which the particle possesses in virtue of its motion and its position; this is in fact the origin of the term energy. - The terms due to F in (33) are such as would arise from frictional
**resistances**proportional to the absolute velocities of the particles, or to mutual forces of resistance proportional to the relative velocities; they are therefore classed as frictional or dissipative forces. - Principle of Least Resistance.Where more than one system of
**resistances**are alike capable of balancing the same system of loads applied to a given structure, the smallest of those alternative systems, as waS demonstrated by the Rev. Henry Moseley in his Mechanics of Engineering and Architecture, is that which will actually be exerted but are distinguished by an asterisk. - Because the
**resistances**to displacement are the effect of a strained state of the pieces, which strained state is the effect of the load, and when the load is applied the strained state and the**resistances**produced by it increase until the**resistances**acquire just those magnitudes which are sufficient to balance the load, after which they increase no further. - Relations between Polygons of Loads and of
**Resistances**.In a structure in which each piece is supported at two joints only, the well-known laws of statics show that the directions of the gross load on each piece and of the two**resistances**by which it is supported must lie in one plane, must either be parallel or meet in one point, and must bear to each other, if not parallel, the proportions of the sides of a triangle respectively parallel to their directions, and, if parallel, such proportions that each of the three forces shall be proportional to the distance between the other two,all the three distances being measured along one direction. - Relations between Polygons of Loads and of
**Resistances**.In a structure in which each piece is supported at two joints only, the well-known laws of statics show that the directions of the gross load on each piece and of the two**resistances**by which it is supported must lie in one plane, must either be parallel or meet in one point, and must bear to each other, if not parallel, the proportions of the sides of a triangle respectively parallel to their directions, and, if parallel, such proportions that each of the three forces shall be proportional to the distance between the other two,all the three distances being measured along one direction. - Considering, in the first place, the case in which the load and the two
**resistances**by which each piece is balanced meet in one point, which may be called the centre of load, there will be as many such points of intersection, or centres of load, as there are pieces in the structure; and the directions and positions of the**resistances**or mutual pressures exerted between the pieces will be represented by the sides of a polygon joining Pi h2 ~, ~ those points, as in fig. - P4 represent the centres of load in a structure of four pieces, and the sides of the ~ polygon of
**resistances**P1 P2 P2 P4 represent respectively the direc~ I~~ tions and positions FIG. - Of the
**resistances**ex erted at the joints. - Further, at any one of the centres of load let PL represent the magnitude and direction of the gross load, and Pa, Pb the two
**resistances**by which the piece to which that load is applied is supported; then wifl those three lines be respectively the diagonal and sides of a parallelogram; or, what is the same thing, they will be equal to the three sides of a triangleS and they must be in the same plane, although the sides of the polygon of**resistances**may be in different planes. - Then from the proportionality and parallelism sides of a triangle, there results the following of the load and the two
**resistances**applied to each piece of the structure to the three theorem (originally due to Rankine): If from the angles of the polygon of loads there be drawn lines (Ri, R2, &c.), each of which is parallel to the resistance (as Pi F2, &c.) exerted FIG. - At the joint between the pieces to which the two loads reprfsented by the contiguous sides of the polygon of loads (such as L1, L2, &c.) are applied; then will all those lines meet in one point (0), and their lengths, measured from that point to the angles of Ike polygon, will represent the magnitudes of the
**resistances**to which they are respectively parallel. - When the load on one of the pieces is parallel to the
**resistances**which balance it, the polygon of**resistances**ceases to be closed, two of the sides becoming parallel to each other and to the load in question, and extending indefinitely. - In the polygon of loads the direction of a load sustained by parallel
**resistances**traverses the point O-i i Since the relation discussed in 7 was enunciated by Rankine, an enormous development has taken place in the subject of Graphic Statics, the first comprehensive textbook on the subject being Die Graphische Statik by K. - In considering its properties, the load at each centre of load is to be held to include the
**resistances**of those joints which are not comprehended in the partial polygon of**resistances**, to which the theorem of 7 will then apply in every respect. - By constructing several partial polygons, and computing the relations between the loads and
**resistances**which are determined by the application of that theorem to each of them, with the aid, if necessary, of Moseleys principle of the least resistance, the whole of the relations amongst the loads and**resistances**may be found. - Line of PressuresCentres and Line of Resistance.The line of pressures is a line to which the directions of all the
**resistances**in one polygon are tangents. - Stability of Position, and Stability of Frictio-n.The
**resistances**at the several joints having been determined by the principles set forth in 6, 7, 8, 9 and 10, not only under the ordinary load of the structure, but under all the variations to which the load is subject as to amount and distribution, the joints are now to be placed and shaped so that the pieces shall not suffer relative displacement under any of those loads. - For in the second structure the weights, external pressures, and
**resistances**will balance each other as in the first structure; the weights of the pieces and all other parallel systems of forces will have the same ratios as in the first structure; and the severa] centres of resistance will divide the depths of the joints in the same proportions as in the first structure. - Conditions of Stiffness and Strength.After the arrangement of the pieces of a structure and the size and figure of their joints or surfaces of contact have been determined so as to fulfil the conditions of stabilityconditions which depend mainly on the position and direction of the resultant or total load on each piece, and the relative magnitude of the loads on the different piecesthe dimensions of each piece singly have to be adjusted so as to fulfil the conditions of stiffness and strengthconditions which depend not only on the absolute magnitude of the load on each piece, and of the
**resistances**by which it is balanced, but also on the mode of distribution of the load over the piece, and of the**resistances**over the joints. - The effect of the pressures applied to a piece, consisting of the load and the sispporting
**resistances**, is to force the piece into a state of strain or disfigurement, which increases until the elasticity, or resistance to strain, of the material causes it to exert a stress, or effort to recover its figure, equal and opposite to the system of applied pressures. - Principle of the Equality of Energy and Work.FroIn the first law of motion it follows that in a machine whose pieces move with uniform velocities the efforts and
**resistances**must balance each other. - The symbolical expression of this law is as follows: let efforts be applied to one or any number of points of a machine; let any one of these efforts be represented by P, and the distance traversed by its point of application in a given interval of time by ds; let
**resistances**be overcome at one or any number of points of the same machine; let any one of these**resistances**be denoted by R, and the distance traversed by its point of application in the gi- en interval of time by ds; then ~.Pds=2~.Rds. - Modulus of a Machine.In the investigation of the properties of a machine, the useful
**resistances**to be overcome and the useful work to be performed are usually given. - The prejudicial
**resistances**are generally functions of the useful**resistances**of the weights of the pieces of the mechanism, and of their form and arrangement; and, having been determined, they serve for the computation of the lost work, which, being added to the useful work, gives the expenditure of energy required. - For example, in a machine-work, the steam-engine, which is the prime mover of the various tools, has a flywheel on the crank-shaft to store and restore the periodical excess of energy arising from the variations in the effort exerted by the connecting-rod upon the crank; and each of the slotting machines, punching machines, riveting machines, and other tools has a flywheel of its own to store and restore energy, so as to enable the very different
**resistances**opposed to those tools at different times to be overcome without too great unsteadiness of motion. - To find the distance s through which a brake, exerting the friction F, must rub in order to stop a machine having the total actual energy E at the moment when the brake begins to act, reduce, by the principles of 96, the various efforts and other
**resistances**of the machine which act at the same time with the friction of the brake to the rubbing surface of the brake, and let R be their resultantpositive if resistance, negative if effort preponderates. - To express this symbolically, let Wi, W2 be the weights of the bodies; P the effort exerted between them; S the distance through which it acts; R1, Rf the
**resistances**opposed to the effort overcome by Wi, ~AT2 respectively; E1, Ef the shares of the whole energy E exerted upon Wi, W2 respectively. - He was also the first to demonstrate experimentally the difference of action between what he called a "quantity" magnet excited by a "quantity" battery of a single pair, and an "intensity" magnet with long fine wire coil excited by an "intensity" battery of many elements, having their
**resistances**suitably proportioned. - As the lower block carrying the weight, and in the absence of friction and other
**resistances**the mechanical advantage will be in the same ratio of the effort to the resistance. - In one of these branches is placed a battery B and in another a galvanometer G; the four p Q other
**resistances**are denoted by the letters P, Q, R, S.