a block mass m1 collides with a block of mass m2 such that m1 becomes at rest and m2 slides across the surface until it reaches the frictional surface. the coefficient of friction between m2 and surface is uk. What is the rate of change of the speed of the center of mass of the two block system after m2 enters frictional surface

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

ingenuity says that the answer is 2.7 m.