Couple More Questions on Electrostatics


by Fusilli_Jerry89
Tags: couple, electrostatics
Fusilli_Jerry89
Fusilli_Jerry89 is offline
#1
Jan3-07, 12:13 AM
P: 164
1. The problem statement, all variables and given/known data
1) From the observation that there's an electrostatic attraction between object A and B, what's the most you can conclude about the electric charge on A and B?

2) A plastic sphere with a positive charge of 4.8E-19 C is held stationary in a gravitational field of strength 9.8m/s/s by an electric field of strength 1.2E5 N/C. What is the force of gravity of the sphere?

3)How did Benjamin Franklin define a negative charge?

4) Draw a diagram to show the lines of force around a small positive charge.

5) Point P is 3.0 cm away from a small object with a positive charge of magnitude 5.0 muC. What is the electric field strength at point P?
2. Relevant equations
F=QE
F=kQq/d^2


3. The attempt at a solution
1) One has to be positive and one has to be negative.

2) 1.2E5 N/C=Fg/4.8E-14 N
Fg=5.8E-14 N

3) He defined it as having more electrons than protons.

4)

5) QE=(kQq)/r^2
E=(kq)/r^2
E=[(9.0E9)(5.0E-6 C)]/(0.030m)^2
E= 5.0E7 N/C
Phys.Org News Partner Science news on Phys.org
Better thermal-imaging lens from waste sulfur
Hackathon team's GoogolPlex gives Siri extra powers
Bright points in Sun's atmosphere mark patterns deep in its interior
berkeman
berkeman is online now
#2
Jan3-07, 10:23 AM
Mentor
berkeman's Avatar
P: 39,601
In the diagram, remember that the lines of the electric field (and hence the lines of force) originate on + charges and terminate on - charges. How would that change your drawing some?
Fusilli_Jerry89
Fusilli_Jerry89 is offline
#3
Jan3-07, 10:48 PM
P: 164
you mean drawing the lines out of the positive charge?

berkeman
berkeman is online now
#4
Jan4-07, 12:51 AM
Mentor
berkeman's Avatar
P: 39,601

Couple More Questions on Electrostatics


Quote Quote by Fusilli_Jerry89 View Post
you mean drawing the lines out of the positive charge?
Maybe....

There would be two cases, with variations on those two cases, right? The first would be a simple diplole, where there are two equal charges spaced apart. What would the E field distribution (and therefore the force vector field) look like for that?

The second case is a positive charge embedded in an overall E field that is generated by something external (like a positive ion sitting between the plates of a capacitor). How would that change the E field diagram?


Register to reply

Related Discussions
two questions on electrostatics Introductory Physics Homework 3
Electrostatics Questions Advanced Physics Homework 3
Electrostatics Questions Classical Physics 5
A couple of questions Academic Guidance 1
A Couple Questions......... General Astronomy 3