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--- 184_notes:examples:week3_balloon_wall [2018/02/03 21:16] – tallpaul
+++ 184_notes:examples:week3_balloon_wall [2021/01/26 21:21] (current) – [Solution] bartonmo
@@ Line 1: / Line 1: @@
+[[184_notes:pc_force|Return to Electric Force]]
 =====Example: Balloon Stuck to a Wall=====
 When you rub part of a rubber balloon against wool (or your hair), electrons will leave the wool, which is slightly conductive, and go onto the balloon. The rubber on the balloon is much less conductive (rubber is more of an insulator than wool), and the electrons will not readily leave the balloon. As a result, the balloon becomes negatively charged. Imagine you bring the negatively charged balloon up to a wall, and it sticks (This is possible! A quick internet search will yield many explanations and demonstrations. You can also try it yourself). Why would the balloon stay in one place on the wall? Draw a free body diagram for the balloon to help your explanation.
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   * The wall is perfectly vertical (parallel to the gravitational force).
 </WRAP>
-{{ 184_notes:3_balloon_picture_bare.png?200 }}
+[{{ 184_notes:3_balloon_picture_bare.png?200|Balloon stuck to wall }}]
 ===Goal===
@@ Line 29: / Line 31: @@
 We know the balloon is motionless, so air resistance is not a factor here, as it often is with balloons. The only other force we could have is the electric force between the balloon and the wall. Since the net force on our balloon is zero, the free body diagram looks something the following representation:
-{{ 184_notes:3_balloon_diagram.png?200 |Balloon Force Diagram}}
+[{{ 184_notes:3_balloon_diagram.png?200 |Balloon Force Diagram}}]
 In order to describe how we might get this diagonal electric force, we'll make a few more assumptions.
@@ Line 44: / Line 46: @@
 We can use the following representation, in which the balloon is motionless, to show how we are thinking of the balloon and the wall at this point:
-{{ 184_notes:3_balloon_picture.png?200 |Balloon Stuck to Wall}}
+[{{ 184_notes:3_balloon_picture.png?200 | Balloon Stuck to Wall (with charges shown)}}]
 We know that the balloon is negatively charged from rubbing it on wool/hair. When we bring the charged balloon close to the wall, the atoms in the wall near to the balloon become polarized with the electron clouds being pushed away from the negative balloon. See the notes on [[184_notes:charge_and_matter|Charges and Matter]] for more information on polarization. This means that the negative balloon is now //attracted// to the positive nuclei in the polarized wall. (The balloon is also repelled from the negative electron clouds, but since the nuclei are closer to the balloon, the attractive force is more powerful).