Also got lost on this question: a rescue plane wants to drop supplies to isolated mountain climbers on a rocky ridge 235m below. if the plane is traveling horizontally with a speed of 250 km/h (69.4 m/s), (a) how far in advance of the recipients (horizontal distance) must the goods be dropped. (b) suppose, instead that the plane releases the supplies a horizontal distance of 425 m in advance of the mountain climbers. what vertical velocity (up or down) should the supplies be given so that they arrive precisely at the climbers' position. (c) with what speed do the supplies land in the latter case?

Part a)

Part b)

Explanation:

Part a)

Since we know that the vertical speed of the plane is zero

so here the mass is dropped down with zero initial speed

so we will have

So the horizontal distance moved by it is given as

Part b)

If plane drops the good at distance of 425 m

so the time taken by it to reach is given as

now in vertical direction

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