Warm Up: Get out your homework comparing Fe and Fg Write down what’s wrong with these statements: Positive protons are pulled to the Styrofoam plate. I used an electroscope to tell the charge on the plastic rod. How can you say this sentence using a vocabulary word we have learned? When I brought the glass rod towards the electroscope the electrons moved towards the ball end of the electroscope since a glass rod becomes positively charged when rubbed with silk.

- I can describe the similarities and differences between gravitational and electric force. - So I can explain why microscopic phenomena occur. - I am successful when I can explain why electrons are free to move.

Gravitation vs Electric Force How does Coulombs Law compare to the Law of Gravitation? The electron and proton of a hydrogen atom are separated (on the average) by a distance of about 5.3x10-11 m. Find the magnitudes of the electric force and the gravitational force that each particle exerts on the other. Only one type of gravitational force Two types of electric force (pos and neg)

Gravity is always attractive Electric Force can attract or repel FG based on mass Fe based on charge Both are affected by an inverse square of distance. G (6.667x10-11) <<<k (9x109)

Electrostatics Forces between charged objects at rest. Net charge – excess of either positive or negative charge Net zero or net neutral – NO charge. Conservation of charge – net charge of an isolated system remains constant.

AP Sample Question Jigsaw We will be reviewing 3 sample questions In your group, read and answer the one question given to you. After 5 minutes, new groups will be made. Groups of three will be formed with each person in a group having a different question. Share your answer with the other two partners in your group.

C

C

B