- #1
arileah
- 8
- 2
Homework Statement
An electron is launched at a 45∘ angle and a speed of Vo = 5.0×10^6 m/s from the positive plate of the parallel-plate capacitor towards the negative plate. The electron lands 4.0 cm away.
Homework Equations
F = ma = qE
v = d/t
s = vt -(1/2)at^2
x = 0.04 m
The Attempt at a Solution
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We can find t by using trigonometry:
t = x/(cos45)
yf - yi = 0 = Vo * sin(45) * t - (1/2)at^2
Vo*sin(45) = (1/2)at
using F = ma = qE,
a = qE/m
so,
Vo*sin(45) = t * qE/(2m)
and using t =x/cos(45)
Solving for E,
E = (2m * Vo * sin(45) * cos(45))/(qx)
but cos(45)*sin(45) = 1/2
Therefore,
E = (Vo * m)/(q*x)
At this point I plug in my constants:
Vo = 5*10^6 m/s
m = 9.11 * 10^-31
q = 1.6 * 10^-19
x = 0.04
However I am getting a wrong answer. Could anybody point out where it is I've gone wrong? Thanks!