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  1. ExtravagantDreams

    Potential on a line charge?

    Ok, so then if I wanted to find the capacitance between a line charge and a cylindrical conducting shell around it, since I would have to define a potential difference, could I simply say the potential on the line is zero and the potential at the shell is the negative integral of the electric...
  2. ExtravagantDreams

    Potential on a line charge?

    I know it seems a bit trivial, but what is the potential right at an infinite uniformly charged line? Irregardless of reference point, the Potential will have a ln|s|, where s is the perpendicular distance to the line. Obviously this would result in infinity. At the same time when I...
  3. ExtravagantDreams

    Instantaneous velocity animation

    "2(2.20cm/s)*2(t)i" too many twos
  4. ExtravagantDreams

    Increasing distance

    I am still not understanding. I completed the squares on \vec {C} \dotprod {\frac {d \vec {C}} {dt}} = 0 and get this really complex function that tells me nothing. .5g^2[(t - \frac {3 V_0 sin \theta} {2g})^2 + (2 - \frac {9} {4} sin^2 \theta) \frac {V^2_0} {g^2}] = 0 The scalar...
  5. ExtravagantDreams

    Increasing distance

    thanks for the help, I will have to try that out tomorrow
  6. ExtravagantDreams

    Increasing distance

    hmm perhaps something to do with the tangent must not be perpendicular or turned to the right of C at time t
  7. ExtravagantDreams

    Increasing distance

    Ok, so how does that help? \sin \theta \cos \theta is a function of maximum x-displacement. The attached image shows the vector C that must never decrease in magnatude as the projectile moves along the arc.
  8. ExtravagantDreams

    Increasing distance

    How do I do a cross product of two scalars? I'm sure that's not what you ment. So, how does this help me?
  9. ExtravagantDreams

    Increasing distance

    Well, you got a function of theta only, but I'm not so sure this helps me. I am not trying to find an angle that will give me maximum range, but a maximum angle that will yield increasing distance from the origin.
  10. ExtravagantDreams

    Free Fall Motion

    right, but the initial speed is a velocity with only one component, namely the x But I did put them in the wrong order
  11. ExtravagantDreams

    Adding Vectors

    I have nothing against that. I was just commenting how it is usually writen in books. Your way is a good middle step for if the question asks to write a vector from the info: a vector of length 5 units, 45 degs above the + x-axis... While the way I showed it is often a way a vector is presented.
  12. ExtravagantDreams

    Adding Vectors

    "If you have some other vector which points along the 45 degree line (measured increasing counter-clockwise from the positive x-axis) and is five units long, its components are (5 \cdot \cos 45^o, 5 \cdot \sin 45^o) " This is often also just writen as [\sqrt{\frac{25}...
  13. ExtravagantDreams

    Free Fall Motion

    the initial velocity will be what ever it is, this same velocity is also part of the final. so \Vec {V_f}: [V_x,V_y] = 5\Vec {V_i}: [V_x,0]
  14. ExtravagantDreams

    Increasing distance

    well, I just graphed it over and over using a calculator changing the angle until I got really really close to a non posative slope. sin\theta \times cos\theta has a maximum at 45 deg. Position: x = v_{0x}t = v cos(\theta)t y = v_{0y}t -.5gt^2 = v sin(\theta)t - .5gt^2 Let...
  15. ExtravagantDreams

    Increasing distance

    I'm having trouble getting the answer without doing a guess and check. Q: Find the maximum angle a projectile can be shot so that it's distance from the origin is always increasing. Air resistance negleced. So there is the x and y position based on initial velocity, angle, and time, but I...
  16. ExtravagantDreams

    Diffuculty with notation

    Thanks for the help guys. Yes, the commas were a dumb error and I should have noticed that. So the triple sum was understood to go from one to three? I did not know that \sum_{i,j,k}=\sum_{i=1}^{i=3}\sum_{j=1}^{j=3}\sum_{k=1}^{k=3 } Hence me using the symbols i,j, and k for both a...
  17. ExtravagantDreams

    Direction of Vectors

    Not sure what class this is for but I remember for my first physics class we would write a vector as C [\theta deg. above positive x-axis]
  18. ExtravagantDreams

    Direction of Vectors

    Vectors add just like integers. Add the x components and the y components. Draw yourself a picture for it to make more sense. Once you have your Cx and Cy, you can use your choise of arctan, arcsin with corresponding sides to find the angle.
  19. ExtravagantDreams

    Diffuculty with notation

    Difficulty with notation I've always had trouble with notation, since there are so many ways to write the same thing. This one is for Vector Analysis First off, when speaking of unit vectos, such as i, j, k is it ok to use the notation; {\hat i},{\hat j},{\hat k} ? Such as in...
  20. ExtravagantDreams

    Quick Acceleration question

    have you learned the kinematic equations?
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