Find electron's acceleration and final velocity

  • Thread starter 404
  • Start date
  • #1
404
52
0
An electron has a mass of 9.1*10^-31 kg. Between the electrodes of a cathode-ray tube, it moves a distance of 4.0mm, accelerated by a net electrical force of 5.6*10^-15 N. Assuming it started by rest, find it's acceleration and final velocity.

I found the acceleration to be 6.15*10^15 m/s^2, which is confirmed by the answer book, but how can I get the final velocity without change in time? distance dont help at all if I dont know average velocity...
 

Answers and Replies

  • #2
Nx2
40
0
u have accel, v1, and distance
use (v2)^2= (v1)^2 + 2ad
 
  • #3
OlderDan
Science Advisor
Homework Helper
3,021
2
404 said:
An electron has a mass of 9.1*10^-31 kg. Between the electrodes of a cathode-ray tube, it moves a distance of 4.0mm, accelerated by a net electrical force of 5.6*10^-15 N. Assuming it started by rest, find it's acceleration and final velocity.

I found the acceleration to be 6.15*10^15 m/s^2, which is confirmed by the answer book, but how can I get the final velocity without change in time? distance dont help at all if I dont know average velocity...
Force times distance in the direction of the force is work, and that equals change in kinetic energy.

Edit
OOPs.. two suggestions flying at the same time. They both lead to the same conclusion.
 
  • #4
404
52
0
Ok I see, thanks.
 

Related Threads on Find electron's acceleration and final velocity

Replies
2
Views
1K
Replies
1
Views
1K
Replies
4
Views
1K
Replies
6
Views
29K
Replies
15
Views
2K
Replies
5
Views
25K
Top