My brain has been shocked by this problem dealing with charges and Coulombs law

In summary, the problem statement wants the direction angle measured counterclockwise from the positive x-axis. So a negative value is not okay. Sketch the force vectors and the resultant vector and calculate accordingly.
  • #1
riseofphoenix
295
2
My brain has been shocked by this problem dealing with charges and Coulombs law :(

Physics_zps5a4fa021.png


This is what I did...

F = k*q1*q2/r^2
F = [ (8.99 * 10^9)(4.9 * 10-9)(6.0 * 10^-9) ] / (0.295)^2
F = 0.000000264 / 0.087025
F = 0.0000003034
F = 3.034 * 10^-7 N

F = k*q1*q3/r^2
F = [ (8.99 * 10^9)(4.9 * 10-9)(3.0 * 10^-9) ] / (0.295)^2
F = 0.000000132 / 0.087025
F = 0.0000001519
F = 1.519 * 10^-7 N

Resultant: √ (3.034 * 10^-7)^2 + (1.519 * 10^-7)^2 =√ ( 1.1488262 * 10^-13) = 3.39 * 10^-7

I got it wrong though :(

Please help
 
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  • #2


This looks like an online quiz. What is the class policy on seeking help vs. working independently for unsupervised quizzes?
 
  • #3


Check your value for r in the second calculation.
 
  • #4


LastOneStanding said:
This looks like an online quiz. What is the class policy on seeking help vs. working independently for unsupervised quizzes?

This isn't an online quiz. It's an online homework assignment that's been given to my class through Webassign.
 
  • #5


ap123 said:
Check your value for r in the second calculation.

Oh!
Ok give me a sec. Imma try to change r in the second equation to 0.100...
 
  • #6


F = k*q1*q2/r^2
F = [ (8.99 * 10^9)(4.9 * 10-9)(6.0 * 10^-9) ] / (0.295)^2
F = 0.000000264 / 0.087025
F = 0.0000003034
F = 3.034 * 10^-7 N

F = k*q1*q3/r^2
F = [ (8.99 * 10^9)(4.9 * 10-9)(3.0 * 10^-9) ] / (0.100)^2
F = 0.000000132 / 0.01
F = 0.0000132
F = 1.32 * 10^-5 N

Resultant: √ (3.034 * 10^-7)^2 + (1.32 * 10^-5)^2 =√ ( 1.743 * 10^-10) = 1.32 * 10^-5 (?)"INCORRECT. Your incorrect answer may have resulted from roundoff error. Make sure you keep extra significant figures in intermediate steps of your calculation."

WHAT?
 
  • #7


EDIT

F = k*q1*q2/r^2
F = [ (8.99 * 10^9)(4.9 * 10-9)(6.0 * 10^-9) ] / (0.295)^2
F = 0.000000264 / 0.087025
F = 0.000003037 (there was one extra 0 that i took off here)
F = 3.037 * 10^-6 N

F = k*q1*q3/r^2
F = [ (8.99 * 10^9)(4.9 * 10-9)(3.0 * 10^-9) ] / (0.100)^2
F = 0.000000132 / 0.01
F = 0.0000132
F = 1.32 * 10^-5 N

Resultant: √ (3.037 * 10^-6)^2 + (1.32 * 10^-5)^2 =√ ( 1.834 * 10^-10) = 1.35 * 10^-5

Is that the answer?
 
  • #8


What about direction?

This is what I did...

arctan(0.0000132/0.000003037) = 77.04

I submitted that answer and I got this -.-

"INCORRECT. Examine the diagram and determine which quadrant contains the angle of the net force."

The answer isn't -77 either. :(
 
  • #9


Your force value for the first charge is off by a power of ten. You'd probably be better off sticking with exponential notation than going through fixed point notation; it's too easy to miscount decimal places.

The problem statement says it wants the direction angle measured counterclockwise from the positive x-axis. So a negative value is NOT okay. Sketch the force vectors and the resultant vector and calculate accordingly.
 
  • #10


gneill said:
Your force value for the first charge is off by a power of ten. You'd probably be better off sticking with exponential notation than going through fixed point notation; it's too easy to miscount decimal places.

The problem statement says it wants the direction angle measured counterclockwise from the positive x-axis. So a negative value is NOT okay. Sketch the force vectors and the resultant vector and calculate accordingly.

Oh wait...the answer is -101 according to webassign o_O
Idk how they got that
 
  • #11


Rise...
you can look at the charges and figure out which quadrant the resultant is in,right??
 

Related to My brain has been shocked by this problem dealing with charges and Coulombs law

1. What is Coulomb's law and how does it relate to charges?

Coulomb's law is a fundamental law in physics that describes the force between two charged particles. It states that the force between two charges is directly proportional to the product of their magnitudes and inversely proportional to the square of the distance between them. This means that as the distance between charges increases, the force decreases, and as the charges increase, the force increases.

2. How does an electric shock affect the brain?

An electric shock can cause disruptions in the brain's electrical signals, leading to temporary or permanent damage. It can also cause a release of neurotransmitters, which can affect cognitive functions such as memory, attention, and decision-making.

3. Can a shock to the brain cause long-term effects on mental health?

Yes, a shock to the brain can potentially cause long-term effects on mental health, such as changes in mood, personality, and cognitive abilities. It can also increase the risk of developing conditions such as depression, anxiety, and post-traumatic stress disorder.

4. What should I do if I experience a shock to the brain?

If you experience a shock to the brain, it is important to seek medical attention immediately. Even if there are no visible injuries, the brain may have been affected, and a medical professional can assess any potential damage and provide appropriate treatment.

5. How can I protect my brain from electric shocks?

To prevent electric shocks to the brain, it is important to follow safety precautions when working with electricity, such as using insulated tools and wearing protective gear. It is also essential to regularly maintain electrical equipment and avoid touching exposed wires or outlets.

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