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  1. maxhersch

    Other Not enough time

    I am in my 4th year (3 semesters left including the current one), taking mechanics, E&M, quantum mechanics, and a lab course. For each of the three main courses, we get one problem set per week that's around 5-8 questions. In addition to that there's a lab report due every 1-2 weeks. It really...
  2. maxhersch

    B I want to define a function knowing only it's limits

    This is a random problem I am trying to figure out. The context doesn't matter. I wish to define a function z(x, y) based on the following limits: 1. lim z (x→∞) = 0 2. lim z (x→0) = y 3. lim z (y→∞) = ∞ 4. lim z (y→0) = 0
  3. maxhersch

    I Entries in a direction cosine matrix as derivatives

    This is a somewhat vague question that stems from the entries in a directional cosine matrix and I believe the answer will either be much simpler or much more complicated than I expect. So consider the transformation of an arbitrary vector, v, in ℝ2 from one frame f = {x1 , x2} to a primed...
  4. maxhersch

    I Kronecker Delta and Gradient Operator

    I am looking at an explanation of the gradient operator acting on a scalar function ## \phi ##. This is what is written: In the steps 1.112 and 1.113 it is written that ## \frac {\partial x'_k} {\partial x'_i} ## is equivalent to the Kronecker delta. It makes sense to me that if i=k, then...
  5. maxhersch

    Double Integration in Polar Coordinates

    Yep, just remembered that right as your replied. Thanks
  6. maxhersch

    Double Integration in Polar Coordinates

    1. Homework Statement Integrate by changing to polar coordinates: ## \int_{0}^6 \int_{0}^\sqrt{36-x^2} tan^{-1} \left( \frac y x \right) \, dy \, dx ## 2. Homework Equations ## x = r \cos \left( \theta \right) ## ## y = r \sin \left( \theta \right) ## 3. The Attempt at a Solution So this...
  7. maxhersch

    Estimate Vector Field Surface Integral

    I assume this is a simple summation of the normal components of the vector fields at the given points multiplied by dA which in this case would be 1/4. This is not being accepted as the correct answer. Not sure where I am going wrong. My textbook doesn't discuss estimating surface integrals...
  8. maxhersch

    Gravitational Lensing and Angular Diameter Distances

    1. Homework Statement Given this diagram, the problem is to find an expression for β/ΘE in terms of X/ΘE and Y/ΘE. 2. Homework Equations β = Θ – α(Θ) Dsβ = DsΘ – Dlsα'(Θ) 3. The Attempt at a Solution I really only need help starting this problem. In my textbook and every document I can...
  9. maxhersch

    Testing Difficulty with Modern Physics Midterm

    2-3 hours is just on the one homework assignment that is due each week. That does not count time spent studying for the weekly quizzes or just reviewing lecture material. And also the same question in my reply above is really what I was looking for. Thanks.
  10. maxhersch

    Testing Difficulty with Modern Physics Midterm

    Sorry I didn't mean to sound like I'm not interested in learning the harder problems but I am in multivariable calculus, advanced statistics, and principles of astrophysics as well and I don't just have time to be delving into subjects I don't think I will be tested on. Believe me I would love...
  11. maxhersch

    Testing Difficulty with Modern Physics Midterm

    I am currently in Honors Physics 3 which is the third introductory course of my physics degree program and covers modern physics beginning with special relativity. So far we have covered Lorentz transformations and velocity additions, relativistic energy and momentum, blackbody radiation, photon...
  12. maxhersch

    I Find the formula to express the infinite series...

    Never mind I figured it out $$a_n = \frac {9 - 7 \{ -1 \} ^n} {2 \{ 1 + n^2 \}}$$
  13. maxhersch

    I Find the formula to express the infinite series...

    The problem is to find the general term ##a_n## (not the partial sum) of the infinite series with a starting point n=1 $$a_n = \frac {8} {1^2 + 1} + \frac {1} {2^2 + 1} + \frac {8} {3^2 + 1} + \frac {1} {4^2 + 1} + \text {...}$$ The denominator is easy, just ##n^2 + 1## but I can't think of...
  14. maxhersch

    SigFigs in Volume and Uncertainty?

    Thanks, so just to be clear that would mean that I should express the change in volume and the uncertainty in the change in volume to the nearest thousandth of a centimeter because they were measured to that degree of accuracy in the question, right?
  15. maxhersch

    SigFigs in Volume and Uncertainty?

    1. Homework Statement A car engine moves a piston with a circular cross section of 7.500 ± 0.005cm diameter a distance of 3.250 ± 0.001cm to compress the gas in the cylinder. (a) By what amount is the gas decreased in volume in cubic centimeters? (b) Find the uncertainty in this volume. 2...
  16. maxhersch

    Angular Momentum: Inelastic Collision of Disk-Ball System

    1. Homework Statement A uniform disk of radius R=1m rotates counterclockwise with angular velocity ω=2rads/s about a fixed perpendicular axle passing through its center. The rotational inertia of the disk relative to this axis is I=9kg⋅m2. A small ball of mass m=1 is launched with speed v=4m/s...
  17. maxhersch

    Work and Rotational Kinetic Energy (Falling Chimney)

    1. Homework Statement A tall, cylindrical chimney falls over when its base is ruptured. Treat the chimney as a thin rod of length 49.0 m. Answer the following for the instant it makes an angle of 32.0° with the vertical as it falls. (Hint: Use energy considerations, not a torque.) (a) What is...
  18. maxhersch

    Conservation of Energy w/ Frictional Forces

    Ahh knew I missed something basic. Thanks a lot.
  19. maxhersch

    Conservation of Energy w/ Frictional Forces

    583.1 is the distance the rock slides found by the Pythagorean Theorem √3002+5002. I tried both positive and negative with those answers. I assume the work done by friction is always negative since it is opposite the motion. and the kinetic energy should be positive because the velocity would be...
  20. maxhersch

    Conservation of Energy w/ Frictional Forces

    1. Homework Statement During a rockslide, a 710 kg rock slides from rest down a hillside that is 500 m long and 300 m high. The coefficient of kinetic friction between the rock and the hill surface is 0.23...