Recent content by quantumtimeleap

  1. Q

    Photoelectric effect experiment: is current proportional to charging time?

    thank you, everyone! the data did turn out exhibiting something more complicated than a simple linear relationship ## I = k \frac{1}{\Delta t} ## for a proportionality constant k.
  2. Q

    Photoelectric effect experiment: is current proportional to charging time?

    I'm not really sure where to put this question, but definitely this is just an introductory physics coursework. Let me refresh you first with the basics of the photoelectric effect. We all know that in the photoelectric effect the stopping voltage is just the kinetic energy obtained by the...
  3. Q

    Calculating Pendulum Angle and Amplitude: Homework Question and Equations

    Yes, Dr. D is correct up there. Think what the definition of angular frequency is Warning: angular frequency is a bit different from frequency in Hertz you get from graphs as the number of full wavelengths per second. You already know the relationship between angular frequency and length of the...
  4. Q

    Direction of E-Field in 3d space

    Just specifying the vector completely (not just its magnitude) automatically gives the direction of the vector. You expressed the vector in Cartesian unit vectors. That already gives its direction. We have to know exactly what the problem is asking for. A more well-phrased question could be...
  5. Q

    What Angle Should You Aim the Launcher to Hit a Target 10 cm Above the Floor?

    Hi there! Don't get scared of being a little creative and putting algebra to your advantage! :) Here's a hint: for the two equations put the trigonometric term (## \sin(\theta) ## or ## \cos(\theta) ## ) on one side and the rest on the other side. Now divide the two equations. You should get ##...
  6. Q

    Energy problem (compression of a spring)

    Hi there! It would have been clearer and easier for us to help you if you indicated what numerical answers you got using which equation, rather than just putting the numbers out there. Anyway, I think you have the equations right. Just equate the energy of the clay at the top ( ## E = KE +...
  7. Q

    Linear Momentum Algebraic interpretation

    Here's a hint. You do have to use algebra here, but this is only a qualitative question where you have to find the relationship ## \frac{KE_1}{KE_2} = constant = \alpha(m_1, m_2) \frac{p_1^2}{p_2^2} ## where ## \alpha ## is a function of the two masses. Once you find this relationship, you can...
  8. Q

    Partial Derivatives multivariable

    if you're talking about calculating spatial derivatives, yes you keep t constant when differentiating. but in general t cannot be a constant. it is one of the independent variables, the four coordinates, (x,y,z,t)
  9. Q

    Challenging Integrals in Calculus 1-2: Expand Your Problem-Solving Skills!

    You don't. You use a power series for that one. Hahaha.
  10. Q

    Trying to find the infinite sum of e^-x using integration

    Hi! I'm new here at PF ^^ I believe you're not going to be able to use the Riemann integral definition with a summation of that form. You are trying to use 1/m as the ##\Delta x ## in the definition of the Riemann sum: ## \sum_{n=0}^\infty f(x) \Delta x ## However 1/m cannot be a difference...
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