University Announcements: Coulomb's Law Examples and Electric Field Definition, Study notes of Law

Download University Announcements: Coulomb's Law Examples and Electric Field Definition and more Study notes Law in PDF only on Docsity! Announcements Jan 11 • Yes the University is open all day (?) • Webassign Online forum schedule: – Fri, Sat, Sun, Mon. evenings 7-10pm before a homework is due on a Tuesday morning – See web site • Help labs have started – See course web page for details http://www.physics.utah.edu/~woolf/2020_Jui/help_lab.pdf 1 18.5 Coulomb’s Law Example A Model of the Hydrogen Atom In the Bohr model of the hydrogen atom, the electron is in orbit about the nuclear proton at a radius of 5.29x10-11m. Determine the speed of the electron, assuming the orbit to be circular. 2 18.5 Coulomb’s Law ( )( )( ) ( ) N7.2 m20.0 C100.4C100.3CmN1099.8 2 66229 2 12 21 12 = ××⋅× == −− r qq kF ( )( )( ) ( ) N4.8 m15.0 C100.7C100.3CmN1099.8 2 66229 2 13 31 13 = ××⋅× == −− r qq kF directionx theinr unit vecto thedenotes ˆ Here ˆ5.7N ˆN4.8ˆN7.213121 + +=+−=+= i iiiFFF  5 Example Three Charges on a Line Determine the magnitude and direction of the net force on q1. 2 ij ji ijij r qq kFF ==  where rij represents the distance between qi and qj 6 Example Three Charges not in line Assuming the horizontal to be the x-direction, and vertical the y-direction, determine the magnitude and direction of the net force on q1 7 Example Three Charges not in line Assuming the horizontal to be the x-direction, and vertical the y-direction, determine the magnitude and direction of the net force on q1