or help me set it up + what equations to use and i will pay you.

#18
In walking across a carpet, you acquire a net negative charge of 56μC .

How many excess electrons do you have?
Express your answer using two significant figures.


#22
The distance between neighboring singly charged sodium and chlorine ions in crystals of table salt (NaCl) is 2.82×10−10m.

What is the attractive electric force between the ions?


#23
A charge of 0.070C moves vertically in a field of 0.095T that is oriented 45∘ from the vertical.

What speed must the charge have such that the force acting on it is 11N ?
Express your answer using two significant figures.

for #18. Q = ne where e is the charge on the electron (-1.602 x 10 ^-19 C). and Q = q=56*10^-6 simply rearrange to have n = Q/e, plug the numbers in, and voila~
I.e. (56μC x 10^-6)/ (-1.602 x 10 ^-19 C).

for #22. q1q2=(1.6x10^−19)^2. An attractive force is negative. One of the ions will be negatively charged and the other will be positively charged giving a negative answer.

= (9x109*1.6x10-19*1.6x10-19)/(2.82x10-10)2 = -2.9 x 10^-9

Did I help? I actually have no idea about physics =)

Best regards, Jyu.

This post was edited by JyuVioleGrace on Dec 5 2013 02:50am

Q = ne where e is the charge on the electron (-1.602 x 10 ^-19 C)
So n = 56 x 10^-6/1.602 x 10-19 = 3.496 x 10^(14)

hope this clears up my 50 fg loan from you

Looks like no one is doing #23.

F = Bq * v * sin (90)

e/ I believe. I don't really remember if that's the correct format of the equation. Should be, though.

This post was edited by Sefira on Dec 5 2013 09:15pm