1. Dec 6, 2008

### cbrowne

1. The problem statement, all variables and given/known data

An electron in a cathode ray tube of a TV set enters a region where it accelerates
uniformly from a speed of 3.5 × 104 m/s to a speed of 1.4 × 106 m/s in a distance
of 2.0 cm. (a) What is the acceleration of the electron in this region? (b) How
long is the electron in the region where it accelerates?

2. Relevant equations

3. The attempt at a solution

A) Vi= 3.5 x 104 m/s Vf= 1.4x 106 m/s
d= 0.02 m

(1.4x10^6)2 = (3.5x 10^4)2 + 2a(0.02)

(1.958775 x 10^12) = 2a(0.02)

(1.958775x10^12) = 0.04a
0.04 0.04

4.8969375x 1013= a

*******************************************

b) Vf= Vi+ at

(1.4x10^6)= (3.5x10^4)+ ( 4.8969375x10^13)t

136500 = 4.8969375x10^13t
4.8969375x10^13t 4.8969375x10^13t

= 0.000000003 --> t = 3.0x 10^-9
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Dec 6, 2008

### jmarcian

seems you used the correct equations, everything looks good to me!

3. Dec 6, 2008

### alphysicist

I believe you have a calculator error here; it looks like you dropped a zero on the left hand side. (1.4 million minus 35 thousand does not give a little over a hundred thousand.)

If you correct that, you should get the right answer for the time.

4. Dec 6, 2008

### cbrowne

THANK SOO MUCH FOR NOTICING THAT MISTAKE!! I end up getting 2.8 x10^-8 for my answer. Could you please verify this

5. Dec 6, 2008

### alphysicist

That looks right to me.