Rock at the top of a 20 m tall hill the rock has a mass of 10 kg how much potential energy does it have

2000Joules

Explanation:

Potential energy is the energy possessed by a body by virtue of its position. A body thrown upward covered a particular height(h) and under the action of gravity(g)

Potential energy = mass × acceleration due to gravity × height

Given mass = 10kg g = 10m/s² height = 20m

Potential energy= 10×10×20

Potential energy = 2,000Joules

Potential energy

b.a device that inputs heat into a cool object

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