Recent content by noppawit

Thank you :)

Homework Statement I'm trying to derive the equation of motion of underdamped motion. Homework Equations From F = m\ddot{x} -kx - c\dot{x} = m\ddot{x} m\ddot{x} + c\dot{x} + kx = 0 x_{h}(t) = ae^{\lambda t} \dot{x}(t) = \lambda ae^{\lambda t} \ddot{x}(t) = \lambda^2 ae^{\lambda t}...

I'm solving by using superposition, I would like to ask that my solution is correct or not. By the way, the question is "Find v0" http://www.wisheyebio.com/uploads/Picture1.png

Two isotropic (radiating the same intensity of EM wave in all directions) point sources S1and S2 emit light in phase at wavelength λ and at the same amplitude. The sources are separated by distance 2d=6.00λ. They lie on the axis that parallel to the x-axis, which runs along a viewing screen at...

Would you please make it simpler? I have not learned this before. I learned that P_{avg} = V_{rms}I_{rms}cos(\theta) = V_{rms}I_{rms}\frac{R}{Z} only.

Sorry for my bad Latex typing. :redface: I've edited.

Show that the electric field: E = Emsin(kx-ωt) and magnetic field: B=Bmsin(kx-ωt) satisfy the following equations: -\frac{\partial B}{\partial x} = \mu_{0}\epsilon_{0}\frac{\partial E}{\partial t} and \frac{\partial E}{\partial x} = -\frac{\partial B}{\partial t} I have no idea...

In RL, AC circuit, an AC source vst = 220sin(40000t-45°) is connected to a 60mH inductor and a 3kΩ resistor. Show that the power dissipated in the inductor is zero. The current in this circuit is 0.057A as I calclulated. I know that inductor has no charging role in this circuit. But...

Draw the phasor representation for each of the following signals. Also write the signal as one sinusoid, v(t) = 20cos(200t+45°)+cos(200t) From this equation, do I have to turn to v(t) = A sin (ωt + φ) ? If yes, how can I convert it? Thank you.

Earth's lower atmosphere contains negative and positive ions that are produced by radioactive elements in the soil and cosmic rays from space. In a certain region, the atmospheric electric field strength is 120V/m and the field is directed vertically down. This field causes singly charged...

I am really sick of this problem. For a), I tried by summing of C1+C2+C3, I get 2.4. Then, why I can't get the right answer from 2.4*12=28.8? (The correct answer is 7.2μC) For b) I tried: C2+C4=12μF; then the circuit will be series, which q will be equal in each capacitor. q = C1V1 =...

Capacitor circuit As shown in the figure, capacitor1 (C1=8.0μF), capacitor2 (C2=6.0μF), and capacito3 (C3=8.0μF) connected to 12.0 V battery. When switch S is closed so as to connect uncharged capacitor4 (C4=6.0μF), a) how much charge passes through point P from the battery and b) how much...

Now the problem is what is ramda, so I can change dq to ramda*ds. After that, I will be able to evaluate from 0 to 0.13 for 1/4 of circumference for q1 and evaluate from 0.13 to 0.515 for the rest of circumference for q2.

A plastic rod has been bent into a circle of radius R=8.20cm. It has a charge Q1 = +4.20pC uniformly distributed along one-quarter of its circumference and a charge Q2 = -6Q1 uniformly distributed along the rest of circumference. With V=0 at infinity, what is the electric potential a) at the...

A nonconducting spherical shell of inner radius a=2.00 cm and outer radius b = 2.40 cm has (withing its thickness) a positive charge density p = A/r, where A is a constant and r is the distance from the center of the shell. In addition, a small ball of charge q=45.0 fC is located at that...