Answer with Explanation:
We are given that
Radius of solid core wire=r=2.28 mm=

Radius of each strand of thin wire=r'=0.456 mm=
Current density of each wire=
a.Area =
Where 
Using the formula
Cross section area of copper wire has solid core =
Current density =
Using the formula


Total number of strands=19
Area of strand wire=




b.Resistivity of copper wire=
Length of each wire =6.25 m
Resistance, R=
Using the formula
Resistance of solid core wire=
Resistance of strand wire=
Answer:
86.4 N downward
Explanation:
Force: This can be defined as the product of mass and acceleration of a body.
The S.I unit of Force is Newton(N).
The Expression of force is given as,
F = ma ................ Equation 1
Where F = force of the parachute harness, m = mass of the skydiver, a = acceleration of the skydiver.
Given: m = 72 kg, a = 1.2 m/s²
Substitute into equation 1
F = 72(1.2)
F = 86.4 N down ward.
Hence the force on the parachute harness = 86.4 N downward
Answer:
Explanation:
Given
Speed while running towards east is 
Distance traveled in east direction 
For Another interval you run with velocity


Total displacement

Time for first interval


Time for second interval

total time 

average velocity 

Therefore average velocity is less than