Kinetic Energy of Point Charges

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SUMMARY

The discussion centers on calculating the kinetic energy of two identical 8-μc point charges positioned at x=+/-1.0m after they have moved 2.0m. The electric field (E) is calculated using the formula E=kq/r^2, yielding a value of 71920 V/m. The potential difference (V) can be determined using V=-Ed, and the change in potential energy can be equated to the change in kinetic energy, as the initial kinetic energy is zero. The interaction between the charges does not need to be considered for this calculation, as potential energy is a scalar quantity.

PREREQUISITES
  • Understanding of electric fields and potential energy
  • Familiarity with the formulas E=kq/r^2 and V=-Ed
  • Knowledge of kinetic energy concepts in physics
  • Basic principles of point charge interactions
NEXT STEPS
  • Study the derivation and application of the formula for electric fields (E=kq/r^2)
  • Learn how to calculate potential energy changes in electrostatics
  • Explore the relationship between potential energy and kinetic energy in conservative forces
  • Investigate the effects of multiple point charges on electric fields and potentials
USEFUL FOR

This discussion is beneficial for physics students, educators, and anyone interested in electrostatics and the dynamics of point charges. It provides insights into energy transformations in electric fields.

cuppy
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Identical 8-μc point charges are positioned on the x-axis at x=+/-1.0m and released from rest simultaneously. What is the kinetic energy of either of the charges after it has moved 2.0m?

some relevant formulas are:
E=kq/r^2
V=-Ed
V=U/q

my attempt at the question:
i started by finding the electric field due to the point charge, E=kq/r^2=71920V/m? since i took 1.0m as the distance from the origin.
i'm confused about the next few steps. would it be right to use V=-Ed (with d as 2.0m) to find the potential difference then use V=U/q to get the change in potential energy and finally equate this with the change in kinetic energy?

since the charges were initially at rest the initial KE was zero, the change in kinetic energy would just be the final kinetic energy. but i don't know how to to approach the question since there are two identical charges. would that mean i have to take into account their interaction and actually find the force between them and somehow relate that to kinetic energy?

i think I'm completely off the mark so any hints would be great.
 
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You don't need to find the electric field here. You are right, you can find the change in potential energy and equate it to change in kinetic energy here.

The potential due to the charges is a scalar quantity and so is potential energy, so, you can just add them up without worrying about the vector field.
 

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