Tristan is an engineer working on a design for a new roller coaster. he wants the car to shoot out of the station very fast but needs a superconductor to be able to accomplish this. he is looking at different materials to use on the tracks of the roller coaster. what is necessary for his material to function as a superconductor? check all that apply.
a. t < tc
b. a solid metal conductivity
c. a very cold temperature
d. a low boiling point no resistance

A and C

Explanation:

Some materials can function as superconductor when their Temperature lowers under its critic temperature Tc, which is a really low temperature, close to 0K. This is because the low temperature reduces the internal movements of the particles of the material, this means that electrons will be able to move easily. There is no need for the superconductor to be a metal.

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

the design of a ski jumping suit involves a trade-off between giving the skiers lift to get higher jumps and ensuring the skier does not face a lot of drag before the jump itself. an expansive suit may to lift the skier higher, but at the same time, it will also increase the air resistance. higher air resistance as the skier goes down the slope limits the speed of the jump. a big suit also increases the risk of losing balance or control, especially if there's a strong gust of wind. while technologically enhanced suits a lot, clothing is not the only factor in a ski jumper’s success. gathering speed while skiing down the slope, ensuring good speed on the ramp, and maintaining good body posture and form in the air all contribute to a ski jumper's success.