negative Ep

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Annie Chantasirivisal_4G
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Joined: Wed Sep 18, 2019 12:21 am

negative Ep

Postby Annie Chantasirivisal_4G » Fri Nov 08, 2019 5:51 pm

Does anyone understand why Ep is always negative for interaction potential energy?

I missed Dr. Lavelle's explanation... why does a negative Ep lead to attractive force?

Aadil Rehan 1D
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Re: negative Ep

Postby Aadil Rehan 1D » Fri Nov 08, 2019 6:52 pm

I think it's just a matter of convention. From what I've read though, at least in the realm of electrostatics, potential energy is usually the work that must be done to move an object a certain distance. if the potential energy is negative, it's entirely possible that it means that no work has to be done for the two atoms to move together.

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Re: negative Ep

Postby Jielena_Bragasin2G » Sun Nov 10, 2019 12:20 am

Ep is always negative due to it being an attractive force; similarly gravity, is negative and an attractive force, so gravity can be seen as analogous too Ep.

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Re: negative Ep

Postby 805422680 » Sun Nov 10, 2019 12:41 am

This is because the charges on both the atoms are different i.e. one is positive and the other is negative. When using the equation to calculate Ep, you are multiplying both the charges on the atoms (q1.q2/r^2). Since multiplying a negative by a positive, will always give you a negative answer, Ep is negative for attractive forces (as the charges have to be opposite for attraction to occur.

Nick Lewis 4F
Posts: 111
Joined: Wed Sep 18, 2019 12:18 am

Re: negative Ep

Postby Nick Lewis 4F » Sun Nov 10, 2019 10:24 pm

I think Ep is always negative because when 2 molecules interact, it is usually a likely reaction when Ep is negative. It is likely to happen and when they interact, energy is released, hence the negative sign.

Daniel Yu 1E
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Joined: Sat Aug 24, 2019 12:15 am

Re: negative Ep

Postby Daniel Yu 1E » Sun Nov 10, 2019 10:43 pm

Is Ep the measure of the strength of the bond or how much energy it takes to break the bond or are they the same thing?

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