Answer:
The total resistance of the wire is = 
Explanation:
Since the wires will both be in contact with the voltage source at the same time and the current flows along in their length-wise direction, the two wires will be considered to be in parallel.
Hence, for resistances in parallel, the total resistance, 

Parameters given:
Length of wire = 1 m
Cross sectional area of copper 
Cross sectional area of aluminium wire
![A_{al}= \pi( R^{2}-r^{2})\\\\ = \pi \times [ (2\times 10^{-3} )^{2}-(1\times 10^{-3} )^{2}] =9.42\times10^{-6} m^{2}\\](https://tex.z-dn.net/?f=A_%7Bal%7D%3D%20%5Cpi%28%20R%5E%7B2%7D-r%5E%7B2%7D%29%5C%5C%5C%5C%20%3D%20%5Cpi%20%5Ctimes%20%5B%20%282%5Ctimes%2010%5E%7B-3%7D%20%20%29%5E%7B2%7D-%281%5Ctimes%2010%5E%7B-3%7D%20%20%29%5E%7B2%7D%5D%20%3D9.42%5Ctimes10%5E%7B-6%7D%20m%5E%7B2%7D%5C%5C)
Resistivity of copper 
Resistivity of Aluminium 
Resistance of copper 
Resistance of aluminium 
The total resistance of the wire can be obtained as follows;


∴ The total resistance of the wire = 
Answer:
Primary waves (P-waves)
Explanation:
Due to excess of the energy inside the earth when the tectonic plates begin to slide or fracture then the energy is released in the form of seismic waves, this causes the earthquake.
<u>Two types of seismic waves are generally responsible for the earth quakes:</u>
- body waves
- surface waves
Body waves are of two types:
Primary waves (P-waves)
These are the fastest of all the waves involved in the earth-quake which travel at a speed of 1.6 km to 8 km per second.
They can pass trough solids, liquids and gases. They arrive at the surface as an instant thud.
Secondary waves (S-waves)
They can only pass through the solids and they move slower than the P-waves.
As S-waves move, they displace the rock particles, pushing them outwards perpendicular to the wave-path that leads to the earthquake-related first rolling period.
Surface waves (L-waves/ long waves)
- These waves move along the surface of the earth. They are responsible for the earthquake's carnage.
- They move up and down the Earth's surface, rocking the foundations of man-made structures.
- Surface waves are slowest of the three waves, which means that they are the last to arrive. So at the end of an earthquake usually comes the most powerful shaking.
The first: alright, first: you draw the person in the elevator, then draw a red arrow, pointing downwards, beginning from his center of mass. This arrow is representing the gravitational force, Fg.
You can always calculate this right away, if you know his mass, by multiplying his weight in kg by the gravitational constant

let's do it for this case:

the unit of your fg will be in Newton [N]
so, first step solved, Fg is 637.65N
Fg is a field force by the way, and at the same time, the elevator is pushing up on him with 637.65N, so you draw another arrow pointing upwards, ending at the tip of the downwards arrow.
now let's calculate the force of the elevator

so you draw another arrow which is pointing downwards on him, because the elevator is accelating him upwards, making him heavier
the elevator force in this case is a contact force, because it only comes to existence while the two are touching, while Fg is the same everywhere
Answer 1) The electric field at distance r from the thread is radial and has magnitude
E = λ / (2 π ε° r)
The electric field from the point charge usually is observed to follow coulomb's law:
E = Q / (4 π ε°
)
Now, adding the two field vectors:
= {2.5 / (22 π ε° X 0.07 ) ; 0}
Answer 2)
= {2.3 / (4 2 π ε°) ( - 7/ (√(84); -12 / (√84))
Adding these two vectors will give the length which is magnitude of the combined field.
The y-component / x-component gives the tangent of the angle with the positive x-axes.
Please refer the graph and the attachment for better understanding.