# Electric Field Problem in a Tube

## Homework Statement

An alpha particle (a helium nucleus) is traveling along the positive x-axis at 1425 m/s when it enters a cylindrical tube of radius 0.700 m centered on the x-axis. Inside the tube is a uniform electric field of 5.00x10-4 N/C pointing in the negative y-direction. How far does the particle travel before hitting the tube wall? Neglect any gravitational forces. Note: mα = 6.64x10-27 kg; qα = 2e.

## Homework Equations

Eq=F
d(delta)y=v(int)yt + 1/2at^2
d(delta)x=v(int)xt

## The Attempt at a Solution

(5x10-4)(2)(1.6x10-19) = F = 1.6 x 10-22
F=ma
(1.6 x 10-22)/(6.67 x 10-27) = a = -2.41 x 10-4m/s^2

d(delta)y=v(int)yt + 1/2at^2
-.7= 0 + (.5)(-2.41 x 10-4)(t^2)
t= .007622s

d(delta)x=v(int)xt
d(x)= (1425)(.007622s)= 10.86 m

I'm not sure what I did wrong, but I checked my math twice so I guess it must be something with the process that I took. Please let me know if you can help! Thanks!

LowlyPion
Homework Helper
(1.6 x 10-22)/(6.67 x 10-27) = a = -2.41 x 10-4m/s^2
Just wondering why it's not -2.41 x 104m/s^2

It is. I just make stupid mistakes. Thanks! Do you see anything else wrong with the calculations? I think I calculated it with the right number I just typed it into here wrong.

LowlyPion
Homework Helper
I didn't calculate it out. But now that I did it looks ok for the statement of the problem.

I got 10.85m carrying more precision, but that shouldn't be the problem.