Okay, foregoing erudition because of late hour no witty introduction straight to question
today professor was discussing the exponentially greater power of the electrical force in comparison with the gravitational force. he said that if two people were both only slightly similarly charged, they would repel each other violently. why does nothing of this sort happen in those van de graffen (sp.) experiments where yer hair stands up etc.? also, for i assume you have guessed my subversive motivation, can i rig up some sort of apparatus to fuck with people? if only a few electrons is all it takes, could you blow someone off the planet? i’d think the escape velocity would be too high… maybe a few thousand feet anyway okay i’m rambling now just answer the question thanks
The force of repulsion between liked charged objects is proportional to the amount of charge, and the surface area of both objects, and inversely proportional to the square of the distance between them. If the objects are you, and the Earth, you will need to charge the entire planet, and yourself. As you rise a few centimeters the inverse square law begins to dominate pretty rapidly.
(Also, a minor geometric quibble, the distance from the surface starts very small, so it’s square increases rather dramatically. The distance between centers of mass is already four thousand miles, so you get less drop off on the gravity end of the arithmetic, and therefore don’t fly up all that fast.)
You are gonna need one hell of a Van De Graff generator, by the way, to charge up the entire planet. (not to mention needing a similar planet to charge up in the opposite polarity.)
Tris
Imagine my signature begins five spaces to the right of center.
You don’t get repulsed away (?) from a van de Graff generator because you aren’t charged. You’re neutral. Why are you neutral? Because opposite charges attract. If you charged yourself positive, unless you insulate yourself very well, the charge will be cancelled by the elctrons you pick up from the ground or anything else you touch.
In fact, the charge of even a van de Graff generator is tiny, because any large amount of one charge will attract the other charge, from the air if necessary. That’s why you can never build enough charge to power a spaceship.
You should have asked the question in class, for brownie points if not for better explanations.
