- #1
johnnyboy53
- 8
- 0
Homework Statement
Two 2.0cm diameter disks face each other, 1.0mm apart. They are charged to -10nC and
10nC.
-What is the field strength between the disks?
-A proton is shot from the negative disk toward the positive disk. What launch speed must the proton have to just barely reach the positive disk?
Homework Equations
Q = (10*10^-9)
ε0=(8.85*10^-12)
radius = .1 m
A = area of circle = πr^2
E = E(+) + E(-) = Q/ε0A
vf^2 = vi^2 +2Ax
The Attempt at a Solution
(10*10^-9)/(8.85^10^-12)(π)(.1^2) = 35.5 but the book gives it as (3.6 * 10^6) N/C
b: vf^2 = vi^2 + 2AX
vi= sqrt( vf^2+2(3.6*10^6)(.001))
= 84.85
book has it as 8.5 * 10^5
I think i am supposed to convert the distances meters or I need to do some type of conversion to get from the original answer to N/C units. I get the right answer but the precision is off. What could i be missing? Thanks!