What is the difference between speed and velocity? A.
Speed measures an object's change in position, while velocity measures an object's change in position per unit time.
B.
Speed measures an object's change in position per unit time, while velocity measures an object's change in speed per unit time.
C.
Velocity and speed both measure an object's change in position, but velocity only depends upon the object's speed.
D.
Velocity measures an object's rate and direction of motion, and speed measures rate only.

the answer is mosques. they are an important part of islamic culture.

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

there are no contact forces mentioned on the list of choices that you've provided.