Lect13-Phys172s10-(7.1-7.9.Energy)

# Lect13-Phys172s10-(7.1-7.9.Energy) - Spring 2010 PHYS 172...

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Unformatted text preview: Spring 2010 PHYS 172: Modern Mechanics Lecture 13 – Energy in Macroscopic System Read 7.1– 7.9 !!! CHECK EXAM 1 SCORES !!! 1. You have 2 more days to make sure that you have exam 1 score posted on CHIP and that the score is correct . 2. If your multiple choice part (Ex1M) score is missing or incorrect: contact your instructor immediately 3. If your write-up exam score (Ex1H) is missing or is incorrect: contact your recitation TA immediately 4. No complaints about Exam 1 grading will be considered after 2/27/2010 (the paper copies will be discarded) 5. Check your iClicker scores for lectures 02-12. No complaints will be considered after 3/2/2010 Potential energy of a spring , s x s F k x = - x , s s x U F x ∂ = - ∂ 2 1 2 s s U k x = 2 1 2 s s U k s = Potential energy of a spring: 2 1 2 s k s s U Assume U s = 0 for relaxed spring y Energy of an oscillating spring-mass system x Neglect friction: ( ) 2 Δ = Δ + + = sys s E mc K U 2 2 1 2 2 s mv k x & ¡ Δ + = ¢ £ ¤ ¥ 2 max 1 2 s K U k x = = y 2 max 2 mv K U = = 2 2 max max 1 2 2 s mv k x = x max-x max Maximum speed: Speed at any point: 2 2 2 max 1 1 2 2 2 s s mv k x k x + = ( ) ( ) 2 2 max / s v k m x x =- v c << 1 γ = HOME STUDY: Example, “a rebounding block” k s = 2000 N/m System: block, spring, Earth Assume: no interaction with surroundings γ...
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## This note was uploaded on 05/16/2010 for the course PHYSICS 172 taught by Professor Sergeisavikhin during the Spring '09 term at Purdue.

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Lect13-Phys172s10-(7.1-7.9.Energy) - Spring 2010 PHYS 172...

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