At full energy, protons in the 2.00-km-diameter Fermilab synchrotron travel at nearly the speed of light, since their energy is about 1000 times their rest mass energy. (a) How long does it take for a proton to complete one trip around? (b) How many times per second will it pass through the target area?

Lecture 2 1 iClicker question Y ou place same two charges a distance r apart. Then you double each charge and double the distance between the charges. How does the force between the two charges change a) The new force is twice a large. b) The new force is half as large. c) The new force is four times as large. d) The new force is four times smaller. e) The new force is the same 2 Electric Force - Coulomb’s Law Consider two electric charge1: q and q 2 The electric force F between these two charges separated by a distance r is given by Coulomb’s Law The constant k is called Coulomb’s constant and is given by Coulomb’s law in vector form q 1 2 12 F = k r 2 r 12 12 32 q1 2 q2 (2q) 2 q2 F = k = k → k = k r 2 r2 (2r) 2 r2 Force remains the same 4 Demo: electrostatic charging 5 +++ ---