Electrical force look for my mistake please

  • Thread starter Number1
  • Start date
  • #1
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A small 5.48 g plastic ball is suspended by a
24.7 cm long string in a uniform electric field
of 3980 N/C, as shown.The acceleration of gravity is 9.8 m/s2 , and
the Coulomb constant is 8.99×109 N · m2/C2..
If the ball is in equilibrium when the string
makes a 27.6◦ angle with the vertical as indi-
cated, what is the net charge on the ball?
Answer in units of μC.

This is how i did it.

q= m*g*tanz/e
q= 24.7e-3 * 9.81*tan 24.7 / 3980
q= 31.79545474

Please tell me what is wrong or if i am using the wrong formula
 

Answers and Replies

  • #2
tiny-tim
Science Advisor
Homework Helper
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Hi Number1! :smile:

(have a degree: º and try using the X2 tag just above the Reply box :wink:)
q= 24.7e-3 * 9.81*tan 24.7 / 3980

(I haven't checked the rest of your calculation, but …) that 24.7º should be 27.6º. :smile:
 

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