If you let yourself fall from a bridge above the water for .4 seconds your speed is?

3.91m/s

Explanation:

We can use the equation h=16t^2 to find the height in feet for a free-falling object. The height from the bridge to the water is h=16(0.4)^2=16(0.16)=2.56 ft

Next, we use the equation v=sqrt(2gh) to determine velocity from vertical height. First we must convert feet to meters as velocity is measured in m/s. 2.56ft is about 0.78 meters. Since h=0.78m from the previous equation and g=9.81m/s^2, then your velocity is v=sqrt(2*9.81*0.78)=sqrt(15.3036)=3.911981595

So, your speed/velocity is approximately 3.91m/s

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