m = mass of the penny 
r = distance of the penny from the center of the turntable or axis of rotation
w = angular speed of rotation of turntable
F = centripetal force experienced by the penny 
 centripetal force "F" experienced by the penny of "m" at distance "r" from axis of rotation is given as 
F = m r w²
in the above equation , mass of penny "m"  and angular speed "w" of the turntable is same at all places. hence the centripetal force directly depends on the radius . 
hence greater the distance from center , greater will be the centripetal force to remain in place.  
So at the edge of the turntable , the penny experiences largest centripetal force to remain in place.
 
        
             
        
        
        
I know it’s the Coulomb’s law and that I’m pretty sure the answer would be C.Inverse Square.
        
             
        
        
        
Answer:

Explanation:
Assume both children bodies are point particles. The total moment of inertia about the rotation axis of 2 points particles of mass 16 kg and 25 kg at 1.5 m arm length is

where  are the masses of 2 children
 are the masses of 2 children  are their distance to the center of rotation
 are their distance to the center of rotation

 
        
             
        
        
        
If a mass of a neutron is 1 the electron mass is 0.00054386734 and it's charge is negative. Hope this helps! ;)
        
             
        
        
        
10cm per beat, it would take 3 beats to travel 30cm x