• Support PF! Buy your school textbooks, materials and every day products Here!

Coulombs Law is KILLING ME! please help

  • Thread starter lalablu3
  • Start date
  • #1
1
0

Homework Statement



You remove two socks from a hot dryer and find that they repel with force of 0.002 N when they’re 1 cm apart. If they have equal charges, and you separate the socks until they’re 5 cm apart, what force will each sock exert on the other? Round the answer to 3 significant digits.

Homework Equations



F=8.9*10^9(q1)(q2) / r^2

The Attempt at a Solution



Ive been working on this for over an hour and am frieking out! First I try to solve for the two charges, using .1 (1cm-converted to meter). I know that once I get this, I can use it to change .1 to .5 and solve for F. Problem is I have been having trouble solving for Q!!! which leaves me stuck in the begining.

Please please help, Ive got a midterm in the morning.:confused:
 

Answers and Replies

  • #2
69
0
F=kq1q2/r^2

at .01m, F = .002
Solve for q^2, since q1 = q2
q^2= (0.002)(.01^2) / (8.9e+9)
= 2.25e-17 C
so q1 or q2 equals the square root of q^2:
(2.25e-17)^0.5 = 4.74e-9 C

Then, use these values to solve if r = .05 (just plug them back into the equation)

I hope this helped
 

Related Threads for: Coulombs Law is KILLING ME! please help

Replies
3
Views
2K
  • Last Post
Replies
3
Views
3K
Replies
7
Views
889
Replies
3
Views
664
Replies
3
Views
8K
  • Last Post
Replies
12
Views
7K
  • Last Post
Replies
4
Views
2K
  • Last Post
Replies
1
Views
1K
Top