p235w11_practice_exam_3_2_sol

# A 3 points as i move the object closer to the lens in

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Unformatted text preview: the image move, toward or away from the lens, and why? As you move the object closer to the lens, the image moves farther away. b: (2 points) Does the magnification of the lens increase, decrease, or stay the same, and why? Since the magnification is m = -di/d0, and d0 is shrinking while di is increasing, the magnitude of this magnification is increasing, but it remains negative, and actually becomes more and more negative. 13: (5 points) Transverse waves travel on a string stretched along the x-axis. They have a speed of 8.0 m/s, an amplitude of 7.0 cm, and a wavelength of 0.320 m. The waves travel in the –x direction and the oscillations are parallel to the y-axis. a: (3 points) Find the frequency f, period , and wave number k for these waves. vs = f, so f = vs/ = 8.0 m/s / 0.32 m = 25 Hz, the period then is 0.04 s, and the wave number k is 2/ = 19.63, we can also calculate = 157 b: (2 points) Write a wave function describing this wave. y(x,t) = 0.07sin(19.63x + 157t) 14: (5 points) A vertical tube 2m long and 25 cm in diameter is open at the top. It is filled with water to a depth of 1 m. Take the speed of sound in air to be 340 m/s. a: (3 points) What is the lowest frequency of sound which will produce a strong standing wave in this tube? A tube like this will reflect sound almost entirely off the water surface. It acts like a closed end for the tube. So you expect waves with = 4L(2n+1). Thi...
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## This test prep was uploaded on 02/15/2014 for the course PHYSICS 235 taught by Professor Mckay during the Spring '08 term at University of Michigan.

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