midterm 4

midterm 4 - Version 043/AACCD midterm 04 Turner (58185)...

This preview shows pages 1–3. Sign up to view the full content.

Version 043/AACCD – midterm 04 – Turner – (58185) 1 This print-out should have 19 questions. Multiple-choice questions may continue on the next column or page – fnd all choices beFore answering. 001 10.0 points ±or a certain transverse wave, the distance between two successive maxima is 1 . 81 m and eight maxima pass a given point along the direction oF travel every 14 . 9 s. Calculate the wave speed. 1. 0.971812 2. 0.490798 3. 1.09237 4. 0.904348 5. 1.32194 6. 0.36962 7. 0.552809 8. 0.758942 9. 0.87241 10. 0.344348 Correct answer: 0 . 971812 m / s. Explanation: Let : λ = 1 . 81 m , t = 14 . 9 s , and n = 8 . The Frequency oF wave is f = n T . The wave speed is v = λf = λ n t = (1 . 81 m) 8 14 . 9 s = 0 . 971812 m / s . 002 10.0 points A horizontal platForm vibrates with simple harmonic motion in the horizontal direction with a period oF 2 . 77 s. A body on the plat- Form starts to slide when the amplitude oF vibration reaches 0 . 326 m. ±ind the coe²cient oF static Friction be- tween body and platForm. The acceleration oF gravity is 9 . 8 m / s 2 . 1. 1.82436 2. 0.171156 3. 0.156909 4. 0.471775 5. 0.30402 6. 0.221936 7. 0.42937 8. 0.434756 9. 0.292921 10. 2.03198 Correct answer: 0 . 171156. Explanation: Let : T = 2 . 77 s , A max = 0 . 326 m , and g = 9 . 8 m / s 2 . At each instant, there are two Forces acting on the platForm: the Force responsible For the oscillation F = - kx and the Force oF Friction F s = μN between the body and the platForm. Applying Newton’s second law horizontally, s F x = - kx + F s = ma platform The only Force acting on the block in the horizontal direction is the Frictional Force, so F s = ma block IF the block does not slide, its acceleration is the same as the platForm: a block = a platform set = a The Force oF Friction is F s = μN = μmg and From simple harmonic motion x = A cos ωt . a = d 2 x dt 2 = - 2 cos ωt , so the maximum acceleration is a max = A max ω 2

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

View Full Document
Version 043/AACCD – midterm 04 – Turner – (58185) 2 and the coefcient oF static Friction is μ = A max ω 2 g . Since T = 2 π ω , μ = A max 4 π 2 g T 2 = (0 . 326 m)(4 π 2 ) (9 . 8 m / s 2 )(2 . 77 s) 2 = 0 . 171156 . 003 10.0 points Two harmonic waves traveling in opposite di- rections interFere to produce a standing wave described by y = 2 sin( k x ) cos( ω t ) , where x is in meters, t is in seconds and k = 13 . 823 m 1 . What is the distance between the two adja- cent antinodes? 1. 0.714286 2. 0.277778 3. 0.25641 4. 0.263158 5. 0.47619 6. 0.294118 7. 0.384615 8. 0.227273 9. 0.4 10. 0.625 Correct answer: 0 . 227273 m. Explanation: Let : k = 13 . 823 m 1 . ±or a standing wave y = 2 A 0 sin( k x ) cos( ω t ) and its wavelength is λ = 2 π k = 0 . 454545 m .
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 07/07/2010 for the course PHY 302 taught by Professor Staff during the Summer '08 term at University of Texas.

Page1 / 12

midterm 4 - Version 043/AACCD midterm 04 Turner (58185)...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online