To solve this problem it is necessary to apply the concepts related to the capacitance in the disks, the difference of the potential and the load in the disc.
The capacitance can be expressed in terms of the Area, the permeability constant and the diameter:

Where,
 = Permeability constant
 = Permeability constant
A = Cross-sectional Area
d = Diameter 
Potential difference between the two disks,
V = Ed 
Where,
E = Electric field
d = diameter
Q = Charge on the disk equal to 
Through the value found and the expression given for capacitance and potential, we can define the electric charge as





Re-arranging the equation to find the diameter of the disks, the equation will be:

Replacing,


Therefore the diameter of the disks is 0.03m 
 
        
             
        
        
        
With arms outstretched, 
Moment of inertia is I = 5.0 kg-m².
Rotational speed is ω = (3 rev/s)*(2π rad/rev) = 6π rad/s
The torque required is
T = Iω = (5.0 kg-m²)*(6π rad/s) = 30π 
Assume that the same torque drives the rotational motion at a moment of inertia of 2.0 kg-m².
If u = new rotational speed (rad/s), then
T = 2u = 30π
u = 15π rad/s 
   = (15π rad/s)*(1 rev/2π rad)
   = 7.5 rev/s
Answer: 7.5  revolutions per second.
        
             
        
        
        
The answer should be B) Scientific theories and laws develop from the acquisition of scientific knowledge. Hope this helps you.
        
                    
             
        
        
        
Answer:
A) 3.11 Hrs
Explanation:
Wave speed is given by the formula

now we will have


now the time taken by the wave to move the distance 560 km is given as



t = 3.11 hours