Electrostatic forces and the principle of superposition

AI Thread Summary
Electrostatic forces obey the principle of superposition, meaning the total effect from multiple charges is the sum of individual effects from each charge. A physical quantity is quantized if it can only take on discrete values, such as the energy levels of bound electrons, while a conserved quantity remains constant over time. The discussion highlights the distinction between linear and nonlinear systems, noting that electrostatic forces are typically linear, allowing for straightforward calculations of resultant forces. The conversation also touches on the nature of linearity in systems, emphasizing the importance of correctly identifying distances in calculations involving multiple charges. Understanding these principles is crucial for analyzing electrostatic interactions and their implications in various physical contexts.
anam89
Messages
17
Reaction score
0
1. Explain what is meant by statement that electrostatic forces obey the principle of superposition?
2. what does it mean to say that physical quantityis (a) quantized or (b) conserved.
 
Physics news on Phys.org
The prinicple of superposition means that effects from multiple sources (charge, for example) is simply the sum of effects from each source, considered seperately. It holds for linear systems.

A physical quantity is quantized if measured values can only take on discrete values- energies of bound electrons, for example. A conserved quantity is one that does not change over time.
 
question

when we walk briskly across a carpet, you often experience a sparkon touching a door knob.what causes this?and how might it be prevented?
 
Homework questions?
 
Andy Resnick said:
The prinicple of superposition means that effects from multiple sources (charge, for example) is simply the sum of effects from each source, considered seperately. It holds for linear systems.

I wonder what exactly you mean with a linear system here. The force isn't a linear function of the distance to a charge
 
yes, i mean linear force.
 
kamerling said:
I wonder what exactly you mean with a linear system here. The force isn't a linear function of the distance to a charge

That's a good point. A system characterized by an operator S{} defined as: S{f} = g, where f is the input is considered linear iff

S{a1f1+a2f2} = S{a1f1}+S{a2f2} = a1 S{f1} + a2 S{f2} = a1g1+a2g2. (the a's are constants)

So, for electrostatic force, S{r} = e1*e2/r^2 or whatever. Now for three charges (or two stationary and 1 test charge) we have to be careful to keep track of which r we mean: r1 is the test-charge 1 distance, r2 the test-charge 2 distance. But if you draw a diagram, you can see that the resultant force on the test charge is equal to the summed forces from each of the 2 fixed charges.

Electrostatics and electrodynamics are *usually* linear systems. Nonlinear materials are those that, for example, have a refractive index that varies with intensity. Or performs frequency mixing.

Stress and strain relationships in continuum mechanics are linear only in the limit of infinitesimal deformations. Fluid mechanics is intrinsically nonlinear.
 
Back
Top