Phy107HE2Rev_6per - Today Hour Exam 2 : Wednesday, Oct. 27...

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1 Mon. Oct 25 Phy107 HE 2 review • Hour Exam 2 : Wednesday, Oct. 27 • In-class (1300 Sterling Hall) • Twenty multiple-choice questions 10, 11 (Relativity) • You should bring Your student ID 1 page notes, written double sided Calculator Pencil for marking answer sheet Mon. Oct 25 Phy107 HE 2 review Today • Quickly finish material in Chapter 11. • Review for Hour Exam 2. Mon. Oct 25 Phy107 HE 2 review From Last Time… • General relativity motivated by Equivalence Principle – No experiment can distinguish between force of gravity and an accelerated reference frame. • General relativity does not consider gravity to be a force between massive objects – Mass tells space-time how to curve – Curvature of space-time dictates how objects move. – Objects move along straight line in space-time – Motion independent of mass of object (even light bends) • Leads to effects such as – Gravitational lensing – Black holes Mon. Oct 25 Phy107 HE 2 review Black holes • Light falls in a gravitational field. A sufficiently strong field should bind light into orbits. • When escape velocity equals the speed of light, nothing can emerge. • Inside the Schwarzschild radius light itself cannot escape. • An object condensed within it’s Schwarzschild radius is called a black hole. Mon. Oct 25 Phy107 HE 2 review How do black holes form? • Matter in the earth is held apart by electric forces. • In the Sun, matter is held up by pressure associated with high temperature by nuclear fusion reactions. • At higher density when fusion burns out, gravity can squeeze electrons into protons forming a neutron star. • At even higher densities, a black hole forms Mon. Oct 25 Phy107 HE 2 review Black hole formation • At sufficient density, no known force prevents the complete collapse of matter to a point- a black hole. • Matter falling into black holes provides the only explanation for energetic objects seen throughout the universe. http:// antwrp . gsfc . nasa . gov / apod /ap 010921.html Black hole roaming the Milky Way.
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2 Mon. Oct 25 Phy107 HE 2 review Seeing Holes Light cannot escape from a black hole, so can’t see black hole itself, but can see matter falling into a hole. Gravitational forces stretch and rip matter: heats up. Very hot objects emit in X-rays (interior of Sun) Cygnus X-1. http://www.owlnet.rice.edu/~spac250/steve/ident.html Mon. Oct 25 Phy107 HE 2 review Exam Review: Topics by chapter • Chap 9: EM radiation, light, color Mon. Oct 25 Phy107 HE 2 review Chapter 8: Wave properties Amplitude is the maximum displacement of string above the equilibrium position
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This note was uploaded on 01/05/2012 for the course PHYS 107 taught by Professor N/a during the Spring '08 term at University of Wisconsin Colleges Online.

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Phy107HE2Rev_6per - Today Hour Exam 2 : Wednesday, Oct. 27...

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