1) The figure shows the forces exerted on a block that is sliding on a horizontal surface: the
gravitational force of 40 N, the 40 N normal force exerted by the surface, and a frictional force exerted to
the left. The coefficient of friction between the block and the surface is 0.20. The acceleration of the
block is most nearly
(A) 1.0 m/s2 to the right
(B) 1.0 m/s2 to the left
(C) 2.0 m/s2 to the right
(D) 2.0 m/s2 to the left

the results is a decrease in air temperature with an increase of altitude.

explanation:

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