- #1
cros0
- 4
- 1
Hello. The first image is the question, the second image is from the solutions manual. I don't understand why these answers are negative. Anyone have a clue?
Electric Field question - Why is this answer negative
- Thread starter cros0
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AI Thread Summary
The discussion addresses confusion over why electric field answers are negative in a given problem. It clarifies that electric fields originate from positive charges and terminate at negative charges, with the field direction being crucial for calculations. At a point between a positive and a negative charge, the electric fields from both charges point in the same direction, contributing to a negative value on the horizontal axis. This understanding resolves the initial confusion about the sign of the answers. The explanation effectively clarifies the concept of electric field direction and its implications for the problem at hand.
Hello. The first image is the question, the second image is from the solutions manual. I don't understand why these answers are negative. Anyone have a clue?
- #2
berkeman
Admin
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Sure. (and Welcome to the PF)cros0 said:
Electric field points from positive charges to negative charges. So the E-field at the first negative charge is pointing inward to that negative charge in all directions. The E-field at the positive charge is pointing away from it in all directions. They ask for the sum of the two E-fields at a point between them, so both components point to the left, which is the negative direction on the horizontal axis.
Does that help?
- #3
cros0
- 4
- 1
Seems reasonable enough, and I feel much better now. Thanks!
In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question.
Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point?
Lets call the point which connects the string and rod as P.
Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
This problem is two parts. The first is to determine what effects are being provided by each of the elements - 1) the window panes; 2) the asphalt surface. My answer to that is
The second part of the problem is exactly why you get this affect.
And one more spoiler:
F1=(5000+200)g=5200*10=52000N --> F2=(5000+100)g=5100*10=51000N ?
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