Electrostatic force doesn't affect acceleration EK no.151

[SaintJude]

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Short discussion on point EK 151

2 particles, A&B are held in equilibrium by the gravitational and electrostatic forces between them. Which of the following changes will cause the charges to accelerate towards one another?

A. Mass of A & B is doubled.
C. Charge of A & B is doubled.

I got it right, but does anyone think it's curious that the changing the electrostatic force doesn't affect the acceleration between the particles?

This is especially curious when gravitational force is negligible compared to electrostatic force. (unless the charges are very large)

 

[milski]

The gravity force cannot be making them repel each other, so it has to be the force pushing them together. That means that the electrostatic force is the one pushing them away from each other and that they have the same polarity of charge. Increasing the charge will increase the electrostatic force and break the equilibrium by making them go away from each other.

Going away from each other is the opposite of accelerating towards each other and C is not the right answer. Just because they don't accelerate towards each other does not mean that they staying in equilibrium.

 

[SaintJude]

Mhm, so electrostatic forces can affect acceleration or deceleration (they can be attractive or repulsive). So would lowering the charges magnitudes then cause the particles to accelerate towards one another?

 

[milski]

Mhm, so electrostatic forces can affect acceleration or deceleration (they can be attractive or repulsive). So would lowering the charges magnitudes then cause the particles to accelerate towards one another?

All forces affect acceleration, F=ma is a universal thing. Deceleration is a fancy name for acceleration in a specific direction. And yes, lowering the charges will cause them to accelerate towards one another.