Lizzy Cole is lounging on a raft (initially at rest) in the middle of her pool. She is minding her own business, reading her .55 kg physics book, when Trace thought it would be funny to dump a bucket of water on her. Lizzy, attempting some kind of revenge, chucks her physics book at Trace with a velocity of 3.7 m/s. a. If the raft and Lizzy weigh 620 N, at what velocity does Lizzy and her raft move immediately after the book is thrown? (Note: Lizzy and the raft will move in the opposite direction of the book.)
b. If Lizzy is 2.4 m from the edge of the pool how long does Trace have to run before she reaches the edge?

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