Estimate the average force that a major-league pitcher exerts on the baseball when he throws a fastball. Assume the ball moves in a straight horizontal line with constant acceleration during the pitch. The distance the pitcher moves the ball during a pitch is about twice his arm length, which is about 3.0 ft. The baseball has a mass of 0.010 slugs and it is pitched with a speed of 92 mph.

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