Register to reply

A charge falls from infinity to within r of another charge, find velocity.

by User1247
Tags: charge, falls, infinity, velocity
Share this thread:
Mar13-08, 02:41 PM
P: 17
1. The problem statement, all variables and given/known data
Velocity of an electron that falls to r from infinity?
An electron falls from infinity to r=10^-8m from a charge q1=4.8x10^-19C. What is the velocity of the electron?

2. Relevant equations

3. The attempt at a solution
Potential energy change U. coulomb's constant k=9x10^-9, electron charge q2=1.602x10^-19C, electron mass m=9.11x10^-31kg, kinetic energy Ek=½mv²

set U=Ek => v=(2U/m)^0.5=1.23x10^5m/s

Anyone see where I went wrong? Thanks.
Phys.Org News Partner Science news on
Apple to unveil 'iWatch' on September 9
NASA deep-space rocket, SLS, to launch in 2018
Study examines 13,000-year-old nanodiamonds from multiple locations across three continents
Doc Al
Mar13-08, 03:40 PM
Doc Al's Avatar
P: 41,459
Quote Quote by User1247 View Post
Redo this, paying attention to the power of ten.

Register to reply

Related Discussions
The work required for adding a charge to an infinite charge distribution Advanced Physics Homework 1
Coulombs Law...find q (charge) Introductory Physics Homework 1
Work needed to move charge from infinity to center of sphere... Advanced Physics Homework 2
Find the charge on each capacitor Introductory Physics Homework 3
Net charge VS dipole moment in E field by infinite line charge General Physics 5