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Vector analysis homework question

  • Thread starter chemboy
  • Start date
  • #1
18
0
3 electrons q1, q2, q3 setup in a right angled triangle

q1
|\
| \
q3-q2

charges are

q1 = +2.5 X 10^-17C
q2 = +3.0 X 10^-17C
q3 = +3.5 X 10^-17C

distances between the charges
q1-q3 = .03 m
q1-q2 = .05 m

setup FBD

\
\ 2F1
\
/
/ 3F1
q1

2F1 = k*q1*q2 / .05^2
= 2.7 X 10^-21N
3F1 = k*q3*q1 / .03^2
= 8.75 X 10^-21N

now I think I use cosine law to figure this out

Fnet = 2F1^2 + 3F1^2 - 2(2F1)(3F1)cos45

is this going the right direction, or did I screw up my FBD
 

Answers and Replies

  • #2
18
0
find the magnitude and direction of the force acting on q1
 
  • #3
52
0
Last edited by a moderator:
  • #4
tiny-tim
Science Advisor
Homework Helper
25,832
249
now I think I use cosine law to figure this out

Fnet = 2F1^2 + 3F1^2 - 2(2F1)(3F1)cos45

is this going the right direction, or did I screw up my FBD
Hi chemboy! :smile:

erm … where did 45º come from?

And are you sure that minus should be there? :smile:
 
  • #5
berkeman
Mentor
56,611
6,510
Thread moved to Homework Help forums.
 

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