Between the two of us we arrived at a useful description of the problem and the equations to solve it. Tom's application was IC engines but the calculation is equally useful for steam engines - either cylinder clearance or crosshead guide clearance in engines that employ a crosshead.
The vector B is termed the magnetic field, and it is defined as the vector field necessary to make the Lorentz force law correctly describe the motion of a charged particle. This definition allows the determination of B in the following way  [T]he command, "Measure the direction and magnitude of the vector B at such and such a place," calls for the following operations: Take a particle of known charge q.
Measure the force on q at rest, to determine E. Then measure the force on the particle when its velocity is v; repeat with v in some other direction. Now find a B that makes the Lorentz force law fit all these results—that is the magnetic field at the place in question.
Alternatively, the magnetic field can be defined in terms of the torque it produces on a magnetic dipole see magnetic torque on permanent magnets below. Alternative names for H   Magnetic field intensity Magnetic field Magnetizing field In addition to B, there is a quantity H, which is often called the magnetic field.
Inside a material they are different see H and B inside and outside magnetic materials. The term "magnetic field" is historically reserved for H while using other terms for B. Informally, though, and formally for some recent textbooks mostly in physics, the term 'magnetic field' is used to describe B as well as or in place of H.
Units[ edit ] In SI units, B is measured in teslas symbol: Devices used to measure the local magnetic field are called magnetometers. Important classes of magnetometers include using induction magnetometer or search-coil magnetometer which measure only varying magnetic field, rotating coil magnetometerHall effect magnetometers, NMR magnetometersSQUID magnetometersand fluxgate magnetometers.
The magnetic fields of distant astronomical objects are measured through their effects on local charged particles. For instance, electrons spiraling around a field line produce synchrotron radiation that is detectable in radio waves.
Magnetic field lines[ edit ] Main article: Field line The direction of magnetic field lines represented by iron filings sprinkled on paper placed above a bar magnet. Compass needles point in the direction of the local magnetic field, towards a magnet's south pole and away from its north pole.
Mapping the magnetic field of an object is simple in principle. First, measure the strength and direction of the magnetic field at a large number of locations or at every point in space. Then, mark each location with an arrow called a vector pointing in the direction of the local magnetic field with its magnitude proportional to the strength of the magnetic field.
An alternative method to map the magnetic field is to 'connect' the arrows to form magnetic field lines. The direction of the magnetic field at any point is parallel to the direction of nearby field lines, and the local density of field lines can be made proportional to its strength.
Magnetic field lines are like streamlines in fluid flowin that they represent something continuous, and a different resolution would show more or fewer lines.
An advantage of using magnetic field lines as a representation is that many laws of magnetism and electromagnetism can be stated completely and concisely using simple concepts such as the 'number' of field lines through a surface.
These concepts can be quickly 'translated' to their mathematical form. For example, the number of field lines through a given surface is the surface integral of the magnetic field. Various phenomena have the effect of "displaying" magnetic field lines as though the field lines were physical phenomena.
For example, iron filings placed in a magnetic field, form lines that correspond to 'field lines'. Field lines can be used as a qualitative tool to visualize magnetic forces.
In ferromagnetic substances like iron and in plasmas, magnetic forces can be understood by imagining that the field lines exert a tensionlike a rubber band along their length, and a pressure perpendicular to their length on neighboring field lines.
The rigorous form of this concept is the electromagnetic stress—energy tensor.Meet Inspiring Speakers and Experts at our + Global Conferenceseries Events with over + Conferences, + Symposiums and + Workshops on Medical, Pharma, Engineering, Science, Technology and Business..
Explore and learn more about . Though, the concept of torque originated from Archimedes' work on levers. (“Give me a place to stand and with a lever I will move the whole world.”) It seems tough that he would have come up with the torque equation, since Newton hadn't born yet to provide mathematical expression for force.
home / study / science / physics / physics questions and answers / Write A Definition And Mathematical Expression For Torque. Question: Write a definition and mathematical expression for torque.
Write a definition and mathematical expression for torque. Jan 31, · So how does T = 4 * m * N * B * L * R * i, otherwise known as T = Km * i affect your motor design, and why am I viciously pounding on torque so much?
Because torque is ultimately what hauls you around, and is one of the components of mechanical power attheheels.com you determine roughly how much mechanical power you will need, you can size wires and components appropriately.
Moment of a force, torque, equilibrium of a body Dr Philip Jackson. G.2 Moments, torque and general equilibrium write down an expression for the resultant torque component T X about O, where T X = T.i. G – write mathematical expressions of the relationships in both directions.
1) Write the Rotational First Law as a mathematical expression: 2) What happens to the magnitude aand the direction of the angular velocity of the disk during the application of a steady torque?