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Unformatted text preview: alexander (jra2623) oldhomework 27 Turner (92510) 1 This print-out should have 14 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. 001 10.0 points 19 waves crash onto a beach every 49 . 9 s. What is their frequency? Correct answer: 0 . 380762 Hz. Explanation: Let : n = 19 , and t = 49 . 9 s . Frequency is the number of cycles per unit time, so f = n t = 19 49 . 9 s = . 380762 Hz . keywords: 002 (part 1 of 2) 10.0 points A block on a horizontal frictionless plane is attached to a spring, as shown below. The block oscillates along the x-axis with simple harmonic motion of amplitude A . m k- A + A v x Which statement about the block is cor- rect? 1. At x = A , its velocity is at a maximum. 2. At x = 0, its acceleration is at a maxi- mum. 3. At x = 0, its velocity is zero. 4. At x = A , its displacement is at a maxi- mum. correct 5. At x = A , its acceleration is zero. Explanation: The block oscillates from maximum dis- placements at x = A and x =- A . At those points the velocity is momentarily zero. 003 (part 2 of 2) 10.0 points Which statement about energy is correct? 1. The potential energy of the spring is at a minimum at x = 0. correct 2. The kinetic energy of the block is always equal to the potential energy of the spring. 3. The kinetic energy of the block is at a maximum at x = A . 4. The potential energy of the spring is at a minimum at x = A . 5. The kinetic energy of the block is at a minimum at x = 0. Explanation: From conservation of energy, v = 0 at x = A, so the kinetic energy is zero and the spring potential energy is at its maximum. At x = 0, the spring potential energy is 0 and the kinetic energy is at its maximum. 004 (part 1 of 3) 10.0 points A block of mass 0 . 1 kg is attached to a spring of spring constant 17 N / m on a fric- tionless track. The block moves in simple har- monic motion with amplitude 0 . 17 m. While passing through the equilibrium point from left to right, the block is struck by a bullet, which stops inside the block....
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This note was uploaded on 10/20/2011 for the course PHY 302K taught by Professor Kaplunovsky during the Summer '08 term at University of Texas at Austin.
- Summer '08