Lillian walks her dog every afternoon after school. Today, her dog was not wanting to go down the street that Lillian wanted to walk down. The dog then began pulling on the leash one way, and Jillian pulled on the leash in the opposite direction. If the dog is pulling the leash at 60 N one way, at what force should Jillian pull on the leash in that same direction to obtain and maintain static equilibrium?

see earlier answer

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

snell's law

refractve index = sin incidence / sin refraction