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Página xxiii - A mass of 2^ kilogrammes loses, each 2\ minutes, a velocity of 300 metres per 2 hours. Express in dynes the force acting. 4. Two forces, of 30 dynes and 40 dynes respectively, act on a material particle at right angles to one another. Find the magnitude of their resultant, and the angle that it makes with the direction of the smaller force. 5. A force of 5000 dynes is resolved into others acting at right angles to one another. One of these is 3000 dynes. Find the other component, and the angle that...
Página 26 - If they are identical in mass and in dimensions, we have simply that m' - O § 4. Laws of Magnetism. — There are two fundamental laws in magnetism. I. Like poles repel, unlike poles attract, one another. This simple observed fact needs no comment. II. The force between two poles varies inversely as the square of the distance between them. It may also be stated that the force between two poles ^ and // is proportional to the product px p'.
Página 217 - Kirchhoff has enunciated in the form of two ' Laws ' the principles that must guide us in such an investigation. Law I. — If any number of conductors meet at a point, and if all currents flowing to the point be considered +, and ail currents flowing from the point be considered — , and if the condition of things be steady, or the potential at the point be not altering, then the algebraic sum of the currents meeting at the point must be zero. Or 2 . C = o.
Página 179 - DanielFs cell. — In this the only essential difference from the above is that we have copper in a saturated solution of copper sulphate, instead of platinum (or carbon) in nitric acid. But it is usually constructed having the zinc and acid in the porous pot, while very often the copper itself forms the outside vessel. The zinc may be surrounded by a semi-saturated solution of zinc sulphate, or of common salt, instead of by dilute sulphuric acid. Here the hydrogen reduces the copper sulphate ; sulphuric...
Página 30 - ... the vertical plane, that passes through the geographical north and south points, is called the plane of the geographical meridian. The earth's field can be resolved into a vertical and a horizontal component in this plane, as we shall see further in § 13. It is the horizontal component that acts on the ordinary compass, so that the magnetic axis of the needle will come to rest in this line. Hence, the plane of the magnetic meridian can also be defined as that vertical plane that contains the...
Página 127 - In the CGS system the unit of work is called, the ' erg,' and is the work done when a force of one dyne is overcome through a distance of one centimetre along the lines of force.
Página xxxviii - ... are connected with a galvanometer and the coil can be made to rotate about one of its diameters. On turning the coil half round, the galvanometer needle is momentarily deflected, but on causing it to rotate in one direction continuously and rapidly no effect is produced. Explain these two results. 4. A plane rectangular iron frame is placed vertically so that it faces due magnetic north.