Answer:

Explanation:
We are given that
Diameter of wire=d=4.12 mm
Radius of wire=r

Current=I=8 A
Drift velocity=
We have to find the density of free electrons in the metal
We know that
Density of electron=
Using the formula
Density of free electrons=
By using Area of wire=

Density of free electrons=
Since Speed, V = Distance/Time
Average speed = Total Distance/Total Time
From the given data, Total Distance = 100 + 30 + 75 miles
and Total Time = 2 + 1 + 1 hours
Average Speed = 205/4
Average Speed = 51.25 mph ( or 51mph to the nearest whole number)
At t=0, the particle was at its equilibrium position. The time period is 32 seconds, so in 8 seconds, it will reach the extreme location once, and hence, in 8 seconds, it will cover a distance equivalent to its amplitude.