Recent content by teclo

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    Viscosity Troubles: Solving a Physics Dilemma

    i have never had to work out a problem as such, but in general for drag force you have F = -Cv or F = -Dv^2 where you use the first for very small speeds and the second for large speeds. C and D are constants that depend on the shape of the object and the viscosity of the material
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    Mathematica Plotting y=\frac{(a_0+a_1)\beta}{\beta^2-a_0a_1} in Mathematica

    the problem is that you're using the constants that aren't numbers. i don't think mathematica will do that. use the help browser for plot, i think the command should be something like [Plot, function, {x,a,b}, {c,d}] or something like that, where the things in the fancy brakets give yr...
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    Challenging Math Problems for the Curious Mind

    derive a variation for the nambu-goto action!
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    Electric potential, field and charge density problem check

    it's been a year since I've had e&m, but the first part looks ok. I'm kind of confused on the second part, because you're saying a is a variable. i thought a was a constant? i guess it doesn't really matter, because the general formula on the axis would be a---->x the second one requires...
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    Kinetic energy in polar coordinates

    could you elaborate, please?
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    Why does mass have no effect on stopping distance?

    the m's do cancel out, though. the equation reads (mu)*m*g = m*a, solving for the acceleration you get a = mu*g. this came up in physics 1 a few years ago and i was super confused. of course if there is a braking force applied (not just coasting to a stop) then it's true the lighter one is...
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    Potential Energy - Potential function problem.

    because acceleration does not equal mass/force (you still forgot the negative)
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    Why Does This Differential Equation Epidemic Model Stump Me?

    trust your math skills, not mathematica! (or whatever program you're using). the difference arises if you factor a negative one out before integrating. thus, you are then integrating - 1/p int (1/y-p) using u substitution now requires no extra negative for du. make sense?
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    Potential Energy - Potential function problem.

    not quite, but almost. you forgot the negative when calculating the force.
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    Solving a Differential Equation with Boundary Conditions and Limits

    the first thing you'd want to do is get y as a function of t. whoops, i missed your second post. yes, you want to solve for the function y{t} and take the limit as it goes to infinity. you have the right approach, the integration just gets a little messy (but not bad really, assuming that...
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    Velocity v(t) = b(t-T)^2, find position function x(t)

    the derivative of a constant is zero. what the above equation i posted says is that the velocity (v) is the time derivative of position (x). if you differentiate the initial equation (velocity) you get the acceleration. that's not what you're after.
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    Why does mass have no effect on stopping distance?

    assuming they have the same coefficient of friction, i don't see why the lighter one would stop any faster than the heavier one. F = (mu)N = ma N = (mg)
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    Velocity v(t) = b(t-T)^2, find position function x(t)

    doesn't look like it to me. v(t) = dx(t)/dt what is the derivative of option d?