# Can an electrostatic force repel or just attract?

• ak_47_boy
In summary: The plates snap together with 15kv between them, i would think should be able to repel each other with the same force?
ak_47_boy
[SOLVED] Can an electrostatic force repel or just attract?

Two charged plates can't be made to repel each other right?

ak_47_boy said:
Two charged plates can't be made to repel each other right?

Yes they can, just not on the same potential ofcourse

marlon

So, a positively charged plate will be attracted to a grounded plate and a negatively charged plate will be repelled by a grounded plate.

Sorry if i make no sense, i have myself confused.

Edit: This makes no sense because as long as there is potential difference between the plates they will attract each other. What scenario would cause repulsion?

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No. A ground plate is inherently at 0V. It is connected to Earth which by definition in electronic engineering (and perhaps physics) a source of infinite charge, both positive and negative.

A negatively charged plate will induce a positive charge on an earthed plate and they will attract. A positively charged plate will induce a negative charge on the earthed plate and also attract. It is only if you get like with like...so two positively charged or two negatively charged.

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How would i make two plates repel each other then? I tried hooking the positive of a 15kv hene ballast to two plates and nothing happened. This would work if i had two separate supply's correct?

It's probably because the force that the places exert on each other is too small to be easily observed or measured. Have you tried to calculate it?

ak_47_boy said:
Two charged plates can't be made to repel each other right?
Yes. Since like charges repel and unlike charges attract all you have to do is simply place charge of one sign on one plage and charge of the opposite on the other plate.

Best wishes

Pete

jtbell said:
It's probably because the force that the places exert on each other is too small to be easily observed or measured. Have you tried to calculate it?

The plates snap together with 15kv between them, i would think should be able to repel each other with the same force? I have tried calculating it but i don't know if what i am calculating is correct.

pmb_phy said:
Yes. Since like charges repel and unlike charges attract all you have to do is simply place charge of one sign on one plage and charge of the opposite on the other plate.
Pete

Yes, i have done that and it worked very well. But how do you make them repel each other.

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Perhaps there is some flaw in your experimentation? I am not familiar with a 15kV hene ballast. When you perform the experiment with the plate charges equal and opposite to one another how do you connect the equipment?

How do you connect it in the experiment to charge the plates with like charges?

To make them attract i simply hook the positive to one plate and the negative to the other. In an effort to try to make them repel i hooked the positive to both plates while grounding the negative, and nothing happened.

You seem to have a lot of confusion here. Go back to something simpler. Have you ever played with an electroscope before? Try to figure out the nature of the charge induced in there.

Zz.

ak_47_boy said:
So, a positively charged plate will be attracted to a grounded plate and a negatively charged plate will be repelled by a grounded plate.

Sorry if i make no sense, i have myself confused.

Edit: This makes no sense because as long as there is potential difference between the plates they will attract each other. What scenario would cause repulsion?

hi ak_47_boy i am ricardo19 an aswer to your question

different polarities atract and equal polarities repel
follow this example am sending you, and tell me if it was good for you

Ricardo19 said:
hi ak_47_boy i am ricardo19 an aswer to your question

different polarities atract and equal polarities repel
follow this example am sending you, and tell me if it was good for you

http://www.gcsescience.com/Attract-Repel-Electrostatic-Charges.gif

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The reason that the plates with opposite charges attract so much more than like charged plates repel, if you put the same voltage on them Is that there is much more charge on them. Because the opposite charges attract each other more charge is drawn into the plates. If you put the same charge on the plates this will oppose the buildup of charge.

If you want to compare repulsion and attraction there are two ways:

1 charge the opposite charged plates when they are far away from each other, then disconnect the voltage source and bring them together. you should see the same
repelling force as you previously did.

2 use two sets of plates that you give opposite charges. Disconnect the voltage source and then bring two plates with the same charge together.

If you pull apart a charged capacitor, the voltage will go up.this could lead to leakage, sparks AND BE DANGEROUS IF YOUR CAPACITOR WAS BIGGER THAN 1nF.
I have seen this experiment done. you need to cover the edges of the plates with a good insulator and put some grips on them made of an isolator. Do not put the plates near anything that isn't a good insulator (such as yourself)
If you use 100 cm^2 plates with 1 cm initial distance there isn't any danger, but your charge might easily leak away if you're not careful.

Ok, I have it working just as you described.

Thanks!

I have this project on moon colonisation. when i was researching i came across moon dust aka regolith. this substance has a net positive charge. i thought that some how negatively charging a space suit would solve this problem. is this possible? any other ideas?

Also is it possible to crate a "wall" of electrons or negative electroststic charge, like a shield, around a person?

## 1. Can an electrostatic force only attract objects?

No, an electrostatic force can both attract and repel objects. This force is caused by the interaction between electrically charged particles, and the direction of the force depends on the relative charges of the objects.

## 2. What determines whether an electrostatic force will repel or attract?

The relative charges of the objects involved determine whether an electrostatic force will repel or attract. Objects with opposite charges (positive and negative) will attract each other, while objects with the same charge (positive and positive, or negative and negative) will repel each other.

## 3. Can an electrostatic force repel or attract at a distance?

Yes, an electrostatic force can repel or attract objects even if they are not in physical contact. This is due to the electric field that is created by charged objects, which can act on other charged objects at a distance.

## 4. Does the distance between objects affect the strength of the electrostatic force?

Yes, the strength of the electrostatic force between two objects is inversely proportional to the square of the distance between them. This means that as the distance between objects increases, the force decreases.

## 5. Can an electrostatic force be canceled out?

Yes, an electrostatic force can be canceled out if an equal and opposite force is applied. This can occur when two objects with opposite charges are brought close enough together that the repulsive force between them is balanced by an attractive force.

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