An infinitely long line of charge has linear charge density 3.50×10−12 C/m. A proton (mass 1.67×10−27 kg, charge e) is 15.5 cm from the line and moving directly toward the line at 3000 m/s.

how close does the proton get to the line of charge?

Question

An infinitely long line of charge has linear charge density 3.50×10−12 C/m. A proton (mass 1.67×10−27 kg, charge e) is 15.5 cm from the line and moving directly toward the line at 3000 m/s.

how close does the proton get to the line of charge?

anonymous · Answer

you can simply conserve energy.. the will get closest when its velocity has become zero...b'coz UNTIL the proton has a velocity it will move closer and closer. only when it stops has the entire kinetic energy of it has been stored as system's potential energy.. hoping u are familiar with the formulae of electric potential energy and kinetic energy of particle, a final eqn arises:- 1/2*mass(proton)(initial vel. of proton)^2 = potental enrgy of sys at that pt.(need to integrate)... does this help???