This preview shows pages 1–2. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: Physics 212 Classical and Modern Physics Spring 2008 Solutions for HandIn Set #1 Problem A3 Attractive balloons Each balloon has three forces on it: gravity, tension, and the electric attraction. Heres the free body dia gram for the balloon on the left F e T mg x y We are trying to get an expression for q in terms of m and , so well need to find the tension in terms of these quantities. Consider the ycomponent of the net force: X F y = T cos  mg = ma y = 0 T = mg/ cos Now we consider the horizontal components. The mag nitude of the electric force is F e = k  q 1  q 2  r 2 = kq 2 x 2 Newtons 2nd law gives X F x = F e T sin = ma x = 0 Now solve for q : F e = T sin kq 2 x 2 = mg cos sin q 2 = x 2 mg tan k q = x r mg tan k Wolfson Chapter 2010 + + + + + + + + + + + + + + The positive charges on the balloon all mutually repel. This works against the elastic force, so it makes the bal loon expand. If we used negative charges instead, theyloon expand....
View
Full
Document
This note was uploaded on 04/11/2008 for the course PHYS 212 taught by Professor Ladd during the Spring '08 term at Bucknell.
 Spring '08
 Ladd
 Force, Gravity

Click to edit the document details