Force of Repulsion between two people with 1% more electrons than protons

In summary, Richard Feynman's statement that the force of repulsion between two people with 1% more electrons than protons at arm's length can lift a weight equal to that of the entire Earth can be substantiated through an order-of-magnitude calculation. This calculation involves estimating the number of electrons and protons in an average human body, calculating the charge difference between the two people, and using Coulomb's law to determine the repulsive force. The result shows that the electric force is significantly larger than the weight of the Earth, supporting Feynman's assertion.
  • #1
gsquare567
15
0

Homework Statement


Richard Feynman once said that if two persons stood at arm's length from each other and each person had 1% more electrons than protons, the force of repulsion between the two people would be enough to lift a "weight" equal to that of the entire earth. Carry out an order-of-magnitude calculation to substantiate this assertion.


Homework Equations


F(elec) = k*q^2 / r^2
mass of Earth = 5.9742 × 10^24 kilograms

The Attempt at a Solution


I am stuck with the beginning; how do I know how many electrons that is? And how do I find the charge given the number of electrons?

Thanks a lot!
 
Physics news on Phys.org
  • #2
There is no specific number of protons. You have to figure out a reasonable number using reasonable assumptions. It is not 3 and it is not 1040, but something in-between. You know the mass of an average person, so how many protons is that? Like I said, make some assumptions and use the mass of a proton, which that you can look up. You can also look the charge of an electron which the same in magnitude as the charge of a proton.
 
  • #3
Ok. Amazing. Thanks for the quick reply. Here's what I've come up with:

protons:electrons ~= 1:1

average human mass ~= 6.00x10^4 g

mass of one proton is 1 amu = 1.6607x10^-24 g

mass / amu mass = #protons + #neutrons
-> 6.00x10^4g / 1.6607x10^-24g = 3.61x10^28

divide by 2 to get the # of protons
-> 3.61x10^28 / 2 = 1.80x10^28 protons

--> there are approximately 1.80x10^28 electrons in a human body

1% of that is 1.80x10^26

1 Coulomb = −6.24151 × 10^18 electrons

-> a human body with 1% more electrons than protons has a charge of...
1% of electrons in body / # electrons in Coulomb = -2.88x10^7 C

Say arms length is 1m => r^2 = 1m^2

WOW I GET IT!

F(elec) = k * q^2 / r^2 = (9 * 10^9 N*m^2/C^2) * (-2.88x10^7 C)^2 / 1 m^2
= 7.46 * 10^24 N

weight of Earth = mg = 4*10^15 N

=> the electric force is 2*10^9 times larger than the weight of the Earth (according to this approximation), so it is probably true that the repulsion of two people, each with 1% more electrons than protons, can have a force of repulsion enough to lift a weight equal to that of the entire earth.

How is that?
 
  • #4
Looks fine except for the weight of the Earth. The mass of the Earth is 6x1024 kg.
 
  • #5
Please advise me how to cal the weight of the Earth?? Is it related to the mass of the Earth about 6 x 10^24kg?? Thanks!
 

FAQ: Force of Repulsion between two people with 1% more electrons than protons

1. What is the force of repulsion between two people with 1% more electrons than protons?

The force of repulsion between two people with 1% more electrons than protons is dependent on several factors, including the distance between the two individuals, the charge of the electrons and protons, and the strength of the electromagnetic force. In general, the force of repulsion would be very small and likely undetectable in everyday interactions.

2. Is the force of repulsion between two people with 1% more electrons than protons stronger or weaker than the force of attraction between two people with equal numbers of electrons and protons?

The force of repulsion between two people with 1% more electrons than protons would be stronger than the force of attraction between two people with equal numbers of electrons and protons. This is because the extra electrons would create a larger negative charge, leading to a stronger repulsive force.

3. Can the force of repulsion between two people with 1% more electrons than protons be measured?

In theory, the force of repulsion between two people with 1% more electrons than protons could be measured using specialized equipment and techniques. However, the force would likely be so small that it would be difficult to detect and accurately measure.

4. How does the force of repulsion between two people with 1% more electrons than protons affect their interactions?

The force of repulsion between two people with 1% more electrons than protons may slightly affect their interactions, but it would likely be negligible in most situations. It may cause a slight repulsion or discomfort when in close proximity to each other, but this would be minimal and easily overcome by other factors such as social bonds and emotional connections.

5. Is the force of repulsion between two people with 1% more electrons than protons related to static electricity?

The force of repulsion between two people with 1% more electrons than protons is related to static electricity in that it is caused by the buildup of electric charge on the surface of objects. However, this force is much weaker than static electricity and would not have the same effects or be as noticeable in everyday interactions.

Similar threads

Back
Top