Two loudspeakers face each other, vibrate in phase, and produce identical 406 Hz tones. A listener walks from one speaker toward the other at a constant speed and hears the loudness change (loud-soft-loud) at a frequency of 2.86 Hz. The speed of sound is 343 m/s. What is the walking speed

1.21 m/s

Explanation:

Given :

2 loudspeakers

F2 - F1 = 2.86 Hz

Speed of sound, V = 343

Fo = frequency when listener is at rest = 406Hz

To obtain the walking speed Vo, speed as observer moves away from speaker ;

Vo = [(F2 - F1) * V] ÷ 2 * Fo

Vo = [2.86 * 343] ÷ (2 * 406)

Vo = 980.98 / 812

Vo = 1.2081034

Vo = 1.21 m/s

energy can be converted from one form to another, but it cannot be created or destroyed in ordinary chemical or physical means. do not understand what you are asking but hope this

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