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Re: Calculating the strength of electric force and gravitaional force
Quote:
Originally Posted by geko
I have this problem with a question i need to do. The whole question is
Calculate how many times stronger the electric force is than the gravitaional force, between a proton of charge +e and mass Mp at a distance r from an electron of charge -e and mass Me given that:
e = 1.6 x 10 to -19 C
Me = 9.1 x 10 to -31 kg
Mp = 1.67 x 10 to -27 kg
Ke = 9.0 x 10 to 9 N M C
G = 6.7 x 10 to -11 N m kg
My problem is that the only 2 equations i can think of using for it are coulombs law and newtons law of gravity. The trouble is i dont know r, so i cant simply calculate them out. There's also no point i think in rearranging the formulas for r to find it since i dont know F in either case.
Totally stuck on this, is there another equation that i may have overlooked that i could use? Or maybe something else im overlooking? Any help appreciated.
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You could pick an arbitrary distance (i.e. r=1) for both equations and solve for force or you could solve for a constant in the equation setting them equal:
where constantX is the number of times the electrostatic force is larger than the force of gravity
K c is the electrostatic constant 8.988 x 10^9
both q1 and q2 are positive absolute values 1.6 x 10^-19
And, you should get the electrostatic force being around 10^39 times stronger
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