A1.30-m string of weight 0.0121n is tied to the ceiling at its upper end, and the lower end supports a weight w. neglect the very small variation in tension along the length of the string that is produced by the weight of the string. when you pluck the string slightly, the waves traveling up the string obey the equationy(x, t)=(8.50mm)cos(172rad? m? 1x? 2730rad? s? 1t)assume that the tension of the string is constant and equal to w. how much time does it take a pulse to travel the full length of the string? what is the weight w? how many wavelengths are on the string at any instant of time? what is the equation for waves traveling down the string? a) y(x, t)=(8.50mm)cos(172rad? m? 1x? 2730rad? s? 1t)b) y(x, t)=(8.50mm)cos(172rad? m? 1x+2730rad? s? 1t)c) y(x, t)=(10.5mm)cos(172rad? m? 1x+2730rad? s? 1t)d) y(x, t)=(10.5mm)cos(172rad? m? 1x? 2730rad? s? 1t)

a lot of it means it can be "burned" for energy and sold at one price. if it is scarce, the price will go up

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia