Recent content by jamesrc

  1. J

    Confused with the answer<> seems correct buttht's wrong wrong?

    Are you sure that your solution doesn't satisfy those equations? When you take the square root of a number, how many solutions do you get?
  2. J

    'Simple' Optimization Problem

    What makes you uncomfortable about the answer you got? Would it make you more comfortable to compare the volume if the height were slightly above or below the height you calculated to the volume you got?
  3. J

    Challenging Momentum of Collision Problem

    There is more than one way to solve the first part of a problem. One way, which you may or may not have covered in class yet, is using the work-energy theorem and equating the change in kinetic energy of a car (which is a function of its initial velocity) with the work done by friction...
  4. J

    Confused about the wording of this probability problem

    I think the problem means that there are 10 unique pairs of gloves in the drawer and X is the number of pairs of gloves after randomly choosing 6 individual gloves. So one possibility is that you chose 6 gloves and none of them pair up, meaning that you have 0 pairs (X=0). Another possibility...
  5. J

    Separation of variables help

    You've done the calculus correctly, now you need to do a little algebra. Hint: what's e^(-ln x)?
  6. J

    Intro projectile motion

    If the bullet had an initial muzzle velocity of 0 coming out of the gun, how high would it go? You are given how high the bullet goes and that it is traveling straight up (against gravity). You also need to realize that the bullet's velocity at its highest point is 0. With that information...
  7. J

    MATLAB Problems integrating in a for loop in Matlab

    Your syntax for 'for' isn't right - it should be: for C1 = 1:moments to do what you want. Writing it the way you did only executes the loop once (with C1 = 1).
  8. J

    Simple Kinematics problem.

    The distance you've calculated (for part a) is how far Andrew would have driven in 3.4 seconds if he decided he didn't care about the fox and didn't step on the brakes. At the moment he steps on the brakes, he is going 75 km/hr, but 3.4 seconds later, he is going 0.0 km/hr (he has stopped)...
  9. J

    Graphite vs maple bridge on a cello

    Hi - As a disclaimer, I'll admit up front that I don't know the answer to your question, but I thought it was interesting since I've never used a graphite bridge before. It sounds like you've already started working on the bridge, so if you couldn't find a luthier to work on it for you, you...
  10. J

    MATLAB Need help creating a recursive script in matlab that can do this:

    This should do it: S = sum((1:n).^2); (1:n) creates an array of integers from 1 to n the .^2 squares each element and the sum() function does what it says.
  11. J

    Help with MATLAB problem

    It looks like everything is okay except for your acceleration value - why is your equation for acceleration -g/m? If you look at your data, you will see that the object does move up before it goes down as it should. You have a typo in your 'Relevant Equations' section (what you have for...
  12. J

    Spring Constant of car

    Bearbull24.5, I believe you solved for the frequency incorrectly (when you solved for w as a function of T, did you end up multiplying 2pi by T or dividing 2pi by T; which should you have done)? And further, while you were supposed to divide by 4, you should have an understanding of why that...
  13. J

    MATLAB Matlab GUI: changing multiple lines static text

    Try setting all of your elements as cells (with the braces) so that you end up with a cell array of strings rather than a character array - your error may have something to do with that because with a character array, if A,B,C, etc. cannot have a different number of elements. e.g.: A={'blah...
  14. J

    MATLAB MATLAB tolerance question

    I don't see anything wrong with the way you are doing it. If you want to reduce your two conditions to one condition, you can use absolute value like this: target = 4; % whatever target you want tol = 0.002; % whatever tolerance you want if abs(myVar(i)-target) <= tol . . . or if you'd like...
  15. J

    Slider Crank Problem

    If you know how to solve the problem, you should have an equation for acceleration as a function of theta (you may not know the value of omega, but you know that the angular velocity is a constant). There's no reason you can't plot this function if you scale your y-axis in units of omega^2...
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