A marching band is practicing. The band director sees the drum major hit a drum. How far away is the director if he hears the drumbeat in 0.40 seconds? The speed of sound is 330 m/s.

132 m

Explanation:

We can find the distance at which the director hears the drumbeat with the following equation:

Where:

d: is the distance

v: is the speed of sound = 330 m/s

t: is the time = 0.40 s

Hence, the distance at which the director hears the drumbeat is:

I hope it helsp you!

Explanation:

The sound is one form of mechanical wave, which is propagate at constant speed. Then, the distance between the drum  and the director is:

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