What is the main benefit of AC power compared to DC power?
Through the use of transformers (work only with AC) power can be transmitted long distances with minimum loss of energy.
Related Rates - Ladder leaned against house?
a) the ladder is constant not moving. so z = 24 and dz/dt = 0 and z is the hypotenuse. the horizontal axis will represent x, so x = 8, and dx/dt = -1 ft/sec the vertical axis will be y-axis as 8^2 + y^2 = 24^2 ----> y = 16√(2) x^2 + y^2 = z^2 ------> differentiate with respect to time 2x * dx/dt + 2 * y * dy/dt = 0 x * dx/dt + y * dy/dt = 0 y * dy/dt = - x * dx/dt 16√(2) * dy/dt = - 8 * -1 dy/dt = 8/16√(2) dy/dt = 1/2√(2) dy/dt = √(2)/4 ft/sec down --------- b) when y = 16 x^2 + 16^2 = z^2 ---> x = √(320) 16 * dy/dt = - √(320) * -1 dy/dt = √(320)/16 dy/dt = √(5)/2 ft/sec down -------- c) sin(θ) = 8/24 θ = sin^-1( 8/24 ) sin(θ) = x/z sin(θ) = x/24 ----> start differentiating cos(θ) * dθ/dt = (1/24) * dx/dt dθ/dt = (1/24) * dx/dt / cos(θ) dθ/dt = (1/24) * -1 * sec(sin^-1( 8/24 )) dθ/dt ≈ -0.044 rad/sec ======= free to e-mail if have a question
My hair is falling out and I live near a power line.?
Okay I am 15 years old, turning 16 in a week or so. I know I am too young to be losing the amount of hair I do. I take a shower and I see how much hair I am losing, yeah I know it is normal for people to lose hair but I know not anywhere near as much as I do. When I lose hair the root isn't connected, it is just the hair. I am not balding, my hair grows in real thick, but I don't have it long. My mom, dad, and brother also lose hair but not as much as me. We thought it was the power lines outside our house, you know the ones on streets. They are about 30 feet from our house. Is it the power lines or is it just me? I have wanted to know for a few years now.
How often do elcetricity pylons get struck by lightning? What happens when this happens?
If the lightning strikes just the pylon, nothing very interesting happens -- it just follows the pylon to ground. If any of the charge strikes the conducting wires, the charge will follow the wire to the nearest switchyard, where it will probably pop a circuit breaker, causing a brief outage until the breaker resets. There is no insulation on modern transmission line wires -- you can't make insulation strong enough to keep lightning out.
What is the difference between an insulator and a conductor?
An insulator, also called a dielectric, is a material that resists the flow of electric current. An insulating material has atoms with tightly bonded valence electrons. These materials are used in parts of electrical equipment, also called insulators or insulation, intended to support or separate electrical conductors without passing current through themselves. The term is also used more specifically to refer to insulating supports that attach electric power transmission wires to utility poles or pylons. Some materials such as glass or Teflon are very good electrical insulators. A much larger class of materials, for example rubber-like polymers and most plastics are still "good enough" to insulate electrical wiring and cables even though they may have lower bulk resistivity. These materials can serve as practical and safe insulators for low to moderate voltages (hundreds, or even thousands, of volts). In science and engineering, an electrical conductor is a material which contains movable electric charges. In metallic conductors, such as copper or aluminum, the movable charged particles are electrons (see electrical conduction). Positive charges may also be mobile in the form of atoms in a lattice that are missing electrons (known as holes), or in the form of ions, such as in the electrolyte of a battery. All conductors contain electric charges which will move when an electric potential difference (measured in volts) is applied across separate points on the material. This flow of charge (measured in amperes) is what is meant by electric current. In most materials, the direct current is proportional to the voltage (as determined by Ohm's law), provided the temperature remains constant and the material remains in the same shape and state. Most familiar conductors are metallic. Copper is the most common material used for electrical wiring. Silver is the best conductor, but is expensive. Gold is used for high-quality surface-to-surface contacts. However, there are also many non-metallic conductors, including graphite, solutions of salts, and all plasmas. See electrical conduction for more information on the physical mechanism for charge flow in materials.