# Search results

1. ### Mean free path and acoustics

Hello everyone, I have a question regarding the implication of mean free path and pressure acoustics. I have seen several publications on the internet and also calculated the minimum displacement of a wave in air using the formula dp=v * rho * *2*pi*freq. * dx The values of displacement can...
2. ### Fluid speed in a straight pipe

Hello everyone I have a simple question regarding how to calculate the speed of a fluid in a normal pipe with a constant cross-section If we are given the pressure difference at the two ends of the pipe (P1 and P2) is it possible to calculate the speed of the fluid? (I think I can imagine this...
3. ### Radians and the unit of rotational energy

Hello everyone I have a question regarding radians and the unit of rotational energy (which has been probably asked several times elsewhere but is still confusing for me :-) ). As I understand radian (rad) is a UNIT that is dimensionless (thus cannot be omitted), correct ? Now if I want to...
4. ### Electrostatic force, voltage, electrostatic potential

Hello everyone I am stuck with a problem about voltages (electrostatic potential) and forces. According to capacitor equations the energy stored in the capacitor is: U=1/2*C*V^2 And force is: F = - dU/dx Since U is dependent on V^2, our force can’t be positive (repelling...