JentooPhysics C: E&M

AP® Physics C: Electricity and Magnetism · Unit 9 · Topic 9.3

Turning Points and Energy Graphs

Watch it drawn3 questionsPractice

Watch it explained

  1. How it worksHow does a graph of U versus r show you where a charge speeds up and where it halts?
  2. Worked exampleFind the closest approach of a proton fired at 2 times 106 m/s at a fixed +50 nC charge.
  3. Ties togetherHow is an electric turning point the very same idea as escape velocity in gravity?

Check yourself

Your turn1 of 2
A proton is fired directly at a fixed charge of +59 nC with an initial speed of 4 x 106 m/s. Find its closest approach to the fixed charge. Use proton mass 1.673x10−27 kg, e = 1.602x10−19 C, and k = 8.99x109 N m2/C2.

End of topic.

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