Recent content by Alex Katko

  1. Alex Katko

    Calculate the natural circular frequency ωn of the system

    Okay here is what I have now. Since the spring starts off stretched a bit, I should do a static force balance first, and find the tension in the string and the static displacement of the spring. Doing this I end up with two equations. 1. From the 2m mass, T - 2mg = 0 2. From the 1m mass, kx - 2T...
  2. Alex Katko

    Calculate the natural circular frequency ωn of the system

    I'm pretty bad at understanding pully not sure why. The accelerations should not be equal. I would say the acceleration of the 2m mass is twice the acceleration of the 1m mass
  3. Alex Katko

    Calculate the natural circular frequency ωn of the system

    There was no typo, the answer is 1/3*(k/m)1/2
  4. Alex Katko

    Calculate the natural circular frequency ωn of the system

    Homework Statement Calculate the natural circular frequency ωn of the system shown in the figure. The mass and friction of the pulleys are negligible. The diagram is attached. Homework Equations ωn = (k/m)1/2 The Attempt at a Solution I can see the total mass of the system is 3m. So in the...
  5. Alex Katko

    Is My Solution for the Kirchov's Current Law Differential Equation Correct?

    I thought of doing something like this, but i felt the instructions sortof implied i was supposed to use the solved differential equation to find this. And if my solution to the equation is correct, then it should give me the right value for Rth. Assuming the equation is correct, am i right to...
  6. Alex Katko

    Is My Solution for the Kirchov's Current Law Differential Equation Correct?

    Yeah I should have mentioned it. There is a table of values, but i don't really see how they are useful, besides V(1000) which i gave to you and possibly V(0). I attached that table.
  7. Alex Katko

    Is My Solution for the Kirchov's Current Law Differential Equation Correct?

    But the question asked me for what Vm is as t approaches infinity. So solving for C wasn't really necessary here because I believe that term should just go to 0
  8. Alex Katko

    Is My Solution for the Kirchov's Current Law Differential Equation Correct?

    C was the constant that came out of my integration. I actually solved for C with the initial value V(0) = -64.3 C = -64.3 - (Rth+Rc)((Eth/Rth)+(Vc/Rc))
  9. Alex Katko

    Is My Solution for the Kirchov's Current Law Differential Equation Correct?

    I too was confused on why all of the given voltages were negative. If it helps, there was a bit of information at the top of the page: You are conducting a voltage clamp experiment on a cell in which all of the gated channels have been inactivated. The circuit model of the cell membrane and...
  10. Alex Katko

    Is My Solution for the Kirchov's Current Law Differential Equation Correct?

    Simplifying my setup gives me dVm/dt + Vm(1/Rth + 1/Rc) = (Eth/Rth) + (Vc/Rc) From here i use integrating factor to solve. My integrating factor would be: u(t) = exp(((1/CmRth) + (1/CmRc))t) Finishing some algebra, i get: Vm = (Rth + Rc)((Eth/Rth) + (Vc/Rc)) + Cexp(-((1/CmRth)+(1/cmRc))t)...
  11. Alex Katko

    Is My Solution for the Kirchov's Current Law Differential Equation Correct?

    Homework Statement Using Kirchov’s Current Law (KCL) at the top node of the circuit, write the differential equation for the membrane voltage (Vm). Solve for Vm(t) symbolically,assuming that all other voltages, all resistances, and the capacitance are constant Homework Equations Current law...
  12. Alex Katko

    Mechanical deformation question

    I know that i should use the equation: δ = NL/AE In this case, i looked up E and found it to be 15 KSI. Im trying to find the change in distance between points B and C. Therefore, N should be 2 kips (2000 pounds), L is 150 inches, and A in 0.8 inches squared. Plugging this into the...
  13. Alex Katko

    What variables are needed to find a moment?

    If Fy and Fz are both zero, then the croos product becomes cFxi - bFxj. Therefore, the variables needed are F,c, and b
  14. Alex Katko

    What variables are needed to find a moment?

    Ohh i think i am understanding. Fx = Fi. Fy = 0 Fz = 0
  15. Alex Katko

    What variables are needed to find a moment?

    Performing the cross product gives me: (bFz-cFy)i + (cFx - aFz)j + (aFy - bFx)k. All variables (the 3 components of F and a,b,c show up).
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