Spring07_solutions

# Spring07_solutions - Qualifying Exam Spring 2007 Solutions...

This preview shows pages 1–12. Sign up to view the full content.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Qualifying Exam Spring 2007 Solutions Solution 1 We use energy conservation for this problem, so that the initial potential energy E=mg(L/2) becomes kinetic energy of rotation The rotation of the pencil takes place around its tip, thus the moment of inertia is: . 2 / 2 ω I E = ∫ = = L L M dx x L M I 3 2 . 3 The velocity of the eraser is related to the angular velocity as v= ω L. From here we get gL v 3 = which can be compared with the free fall speed of . 2 gL v free = Solution 2 Solution 3 a.) c.) Solution 4 a.) b.) c.) Solution 5 Solution 6 Solution 7 Solution 8 a.) b.) c.) Solution 9 (a) Electrical resistivity: ρ , the constant of proportionality that relates R = ρ (L/A), where L is the length of a wire, A is the cross-sectional area, and R is the resistance. To measure the resistivity of a conductor, you would measure the length of the wire, the cross-sectional area, and then the resistance through V=IR or R = V/I (V and I are the voltage and current, respectively) (b) Magnetic susceptibility: χ = M/B, where M is the magnetization, and B is the applied magnetic field. The magnetic susceptibility can be measured in several different ways – the Gouy balance is one method, where you can measure the torque in a magnetic field of a material. The magnet remains stationary while the sample moves, giving an apparent weight loss or gain. sample moves, giving an apparent weight loss or gain....
View Full Document

## This note was uploaded on 03/11/2012 for the course PHY 3900 taught by Professor Staff during the Fall '1 term at FSU.

### Page1 / 15

Spring07_solutions - Qualifying Exam Spring 2007 Solutions...

This preview shows document pages 1 - 12. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online