By using Ohm's law, we can find what should be the resistance of the wire, R:

Then, let's find the cross-sectional area of the wire. Its radius is half the diameter,

So the area is

And by using the resistivity of the Aluminum,

, we can use the relationship between resistance R and resistivity:

to find L, the length of the wire:
Answer:
3.8 secs
Explanation:
Parameters given:
Acceleration due to gravity, g = 9.8 
Initial velocity, u = 11.76 m/s
Final velocity, v = 49 m/s
Using one of Newton's equations of linear motion, we have that:

where t = time of flight of arrow
The sign is positive because the arrow is moving downward, in the same direction as gravitational force.
Therefore:

The arrow was in flight for 3.8 secs
The power developed is 500 W ( to the nearest Watt)
Power(P) is the rate at which work is done. Work done (W) is the product of the force applied on the object and the displacement (s) made by the point of application of the force.


Therefore,

Substitute the given values of force , displacement and time


Thus the Power can be rounded off to the nearest value of 500 W
Answer:
The magnitude of the electric field is 0.1108 N/C
Explanation:
Given;
number of electrons, e = 8.05 x 10⁶
length of the wire, L = 1.03 m
distance of the field from the center of the wire, r = 0.201 m
Charge of the electron;
Q = (1.602 x 10⁻¹⁹ C/e) x (8.05 x 10⁶ e)
Q = 1.2896 x 10⁻¹² C
Linear charge density;
λ = Q / L
λ = (1.2896 x 10⁻¹² C) / (1.03 m)
λ = 1.252 x 10⁻¹² C/m
The magnitude of electric field at r = 0.201 m;

Therefore, the magnitude of the electric field is 0.1108 N/C
The right answer is B. hope this helps you :)