Answer:
a
Solid Wire
Stranded Wire 
b
Solid Wire
Stranded Wire
Explanation:
Considering the first question
From the question we are told that
The radius of the first wire is 
The radius of each strand is 
The current density in both wires is 
Considering the first wire
The cross-sectional area of the first wire is

= >
= >
Generally the current in the first wire is

=> 
=>
Considering the second wire wire
The cross-sectional area of the second wire is

=> 
=> 
Generally the current is

=> 
=> 
Considering question two
From the question we are told that
Resistivity is 
The length of each wire is 
Generally the resistance of the first wire is mathematically represented as
=>
=>
Generally the resistance of the first wire is mathematically represented as
=>
=>
The material that is more closely related to the Styrofoam insulator.
Styrofoam is the term that is used for polystyrene foam in a trademark form. It is a petroleum-based plastic.
Keeping something warm includes the stopping of the transfer of heat from one object to another. This is how insulation works.
Styrofoam is an insulator, which means it'll help keep the heat from the environment out of your cooler. However, you'll still need cooling agents (like ice packs) to make the cooler cold in the first place.
Styrofoam is usually made mostly of air, which means it is a poor conductor of heat, but an excellent convector. It traps the air in small pockets, which blocks the flow of heat energy. This reduces both conduction and convection and makes Styrofoam a good insulator.
To learn more about Styrofoam here
brainly.com/question/21369568
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Answer:

Explanation:
From the question we are told that:
Frictional force 
Coefficient of kinetic friction 
Generally the equation for Normal for is mathematically given by

Therefore


The 4 significant figures of 31,546,000 are all 8 of the digits.