Recent content by sunquick

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    Integrals with infinite well eigenfunctions

    Great! Thank you so much.
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    Integrals with infinite well eigenfunctions

    Thank you for the replies. I see now that I forgot that the expectation value is calculated by integrating the square of the amplitude of the wavefunction, so if the wavefunction is an eigenfunction of the infinite well u_n (x) = A sin(pi*n*x/a), then the expectation value will be...
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    Integrals with infinite well eigenfunctions

    Homework Statement This is problem 17 from Chapter 3 of Quantum Physics by S. Gasiorowicz "Consider the eigenfunctions for a box with sides at x = +/- a. Without working out the integral, prove that the expectation value of the quantity x^2 p^3 + 3 x p^3 x + p^3 x^2 vanishes for all the...
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    Calculating reaction force for sliding plank

    Thank you for replying. I don't know if the trig functions are correct, because I've tried to do this so many times over and I am really confused. I'll try to explain my reasoning: The definition of the x and y coordinates in terms of the angle theta look like polar coordinates, so I reasoned...
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    Calculating reaction force for sliding plank

    Thank you for your answer. I think you're right, the signs are indeed wrong. Reversing the signs I get I_0 \theta = - N_y L \sin(\theta) + N_x L\cos(\theta) Going through till the end I get \sin(\theta) = \cos(\theta) This equation has one solution between 0 and Pi/2, which is Pi/4, but I...
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    Calculating reaction force for sliding plank

    Homework Statement A plank of length 2L leans against a wall. It starts to slip downward without friction. Show that the top of the plank loses contact with the wall when it is at two-thirds of its initial height. (from Kleppner&Kolenkow,An Introduction to Mechanics 1st ed., problem 6.41)...
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    Calculating Torque around moving Centre of mass

    Homework Statement A man of mass M stands on a railroad car which is rounding an unbanked turn of radius R at speed v. His center of mass is height L above the car, and his feet are distance d apart. The man is facing the direction of motion . How much weight is on each of his feet? Homework...
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    Heat capacity of water -- experimental determination

    Sorry I forgot tho type that part of the problem: a) Explain the general form of the experimental results. b) What quantitative results can you deduce from the observations? For part a) I have to explain that heat is transferred to the ice, increasing its temperature, till it reaches 0ºC...
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    Heat capacity of water -- experimental determination

    Homework Statement A quantity of water in a beaker of negligible thermal capacity is cooled to a few degrees below freezing point. The beaker is then placed in a warm room, and the times recorded at which it is at various temperatures as it gradually warms. The observations were...
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    Frobenius method for Hermite Equation

    Homework Statement I'm asked to solve the Hermite Differential Equation y''(x) - 2 x y'(x) + \lambda y(x) = 0 using the Frobenius method 2. Homework Equations I am to assume the solution is in the form y(x) = \sum a_n x^{n+r} where r are the roots of the indicial equation that in this...
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    Specific heat capacity of copper

    Ooops I did use P =I R^2, I'm so embarrassed right now. I don't know about what is meant by steady conditions. I thought it meant dQ/dt = 0, but why wouldn't that be what they are really trying to say? I don't know exactly how much copper is in the calorimeter, should I assume some length of...
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    Specific heat capacity of copper

    Homework Statement A solid copper cylinder, 50 mm long and of 10 mm radius, is suspended in a vacuum calorimeter. Wound on the cylinder is a length of fine copper wire which is used as heater and resistance thermometer. Initially the resistance of the heater is 100.2 Ω. A current of 100 mA is...
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    Classical An Introduction to Mechanics by Daniel Kleppner and Robert J. Kolenkow

    alternatives for SR I own a copy of the first edition, but I'm still on the fence about the second edition. Do you think I can study the first edition and supplement the chapters on relativity with some other book, like David Morin's Introduction to classical mechanics, or A.P.French's book on...
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    Power of constant force for a given displacement

    Thank you for the replies. I was trying to calculate the power at the end of the motion, y=1.5 m . At that instant I can calculate the power, since I care only for the final velocity, which I know, then P = F v. The second approach P = W/t is valid in this case to calculate the instantenous...
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