Part I: Electrostatics 1. After a comb is rubbed on a wool sweater, it is able to pick up small pieces of paper. Why does the comb lose that ability after a few minutes? 2. A rubber rod can be charged negatively when it is rubbed with wool. What happens to the charge of the wool and why? 3. If the rubber rod from question 2 is brought close to a pith ball and the pith ball repels, what charge does the pith ball have? 4. Suppose you hang a long metal rod from silk threads so that the rod is isolated. You then touch a (+) charged glass rod to one end of the metal rod. Describe the charges on the metal rod. 5. When bubbles are blow at a (-) charged Van de Graaf sphere, they are initially attracted and then very quickly repelled. a. What is the initial charge of the bubbles and why? b. What charge do the bubbles take on when repelled? Why? c. What type of charge transfer occurred since the bubbles and sphere never touched? 6. If you comb your hair on a dry day, the comb can become positively charged. Can your hair remain neutral? Why?Force of Charge Problems 1. If I double the charge of an object, how will the affect the force exerted? Justify. 2. If you have like charges, what type of force will you have? What if you have opposite charges? 3. If you triple the distance between two charged objects, how will that affect the force? 4. You have two positively charged spheres. One sphere has 3 times the charge of the other sphere. If they are 0.16 m apart and the force between them is 0.28 N, what are the charges of the two spheres? 5. A small sphere of charge 2.4 x 10" C experiences a force of 0.36 N when a second sphere of unknown charge is placed 5.5 cm from it. What is the charge of the second sphere