Drop Definition and 876 Threads

  1. S

    Will voltage drop and fluctuation occur?

    Hello, We have a mini split AC Inverter. We need electrical wire for the second mini split AC inverter. Can we get a wire branch from the first AC terminal? Do the voltage drop/sag and fluctuation occur?
  2. C

    I Calculating the change of the volume of a sphere using this integral

    I have a spherical cap of liquid (drop) that rests on a substrate. The substrate has a small hole at the base where liquid is pumped into the drop. One way to parameterize the spherical cap is via: $$x = \sin(s)\cos\phi/\sin\alpha, \,\,\,y=...
  3. L

    B How do I calculate the drop force on a cord and eye bolt?

    i have a question. I have set up an expierment and need some values. I have a round, 3d printed disk, 0.25 inches thick and 4 inches in diameter. In the center, i have a eye-bolt attached. I have hooked up a chain to the eyebolt and some weight to the chain. I have 40Lbs hanging right now and...
  4. Lay1

    Understanding Voltage Drop in a Circuit

    Here is the figure mentioned above. My thinking is that for maximum current, resistance must be minimum. Thus, R1 is not considered which means the voltage drop of R2 is 10V. So, R2 is 1kohm. For minimum, I=2mA, so R1+R2=5kohm, since R2 is 1kohm, R1 must be 4kohm. This is how I deduce. However...
  5. Pushoam

    Surface Tension and Pressure Balance in a Spherical Water Drop

    Taking the shape of water drop to be spherical with radius R and ignoring the gravity, three forces acting on the surface of the water drop are 1) force ##F_o## in radially inwards direrction due to the outside pressure ##P_o## 2) force ## F_{in}## in radially outward direction due to the...
  6. livio

    Estimates of voltage drop with distance in weak electric field

    If I resolve the equation in 0, imposing a voltage value of 5 mV, it gives a non real solution, therefore I cannot resolve it for R=1 because I do not know which voltage value to impose. I am sure this is simpler than I am putting it :) thanks for any advice!
  7. blinkz303

    How to calculate the leak rate based on pressure drop

    I am currently working on a project trying to calculate leak rate and fluid loss from pressurised vessels filled with water over a time period of 30 minutes. So far I have used the Boyles Law which assumes that PV/T = constant which gets us P1 * V1 = P2 * V2 and PdV+VdP = 0 I formed this over to...
  8. J

    Misc. Headwater: 2" drop in a 40 foot length culvert

    I am trying to figure out the fps of 18 inch culvert with 13.5 inches water over the top on inlet and about 2 inches lower on the outlet and 2 inch drop on the outlet end over 40 foot length, what I need to know what would be the headwater on this type of configuration?
  9. J

    Engineering Voltage drop across drain-source for stacked MOSFETs

    Here's the circuut: Vtn is 0.7 V. So Vs1 (wrt ground) cannot be more than 4.3 V else M1 won't turn on. Likewise Vs2 and Vs3 (wrt ground) cannot be more than 4.3 V else M2 won't turn on. So Vs3 = 4.3 V. Even voltage across final resistance is 4.3 V Assume there's no drop across Mosfet. But I'm...
  10. S

    Finding the voltage drop along a tapered wire

    The actual homework question is about finding the voltage of a tapered wire, one where the two ends are different sizes (1cm and 2cm in this case). I've been searching for an equation to do this simply by just plugging in the values I have and I came across this. Where is resistivity, h is...
  11. N

    Pressure drop through volumes of compressible fluid

    Thanks for your response. I'm trying to estimate the pressure in the cavity, i.e. P2. I know the areas, A1 which in practicality is an annulus and A2 which is a 600m pipe with i/d 8mm. I would like to initially understand how to calculate the pressure drop across the annulus. At the moment I'm...
  12. billyt_

    Drop height of a magnet vs. induced EMF in a solenoid

    I am currently working on an experiment that involves dropping a magnet from varying heights and measuring how the induced emf of a solenoid changes as a result. I am currently somewhat struggling with a derivation for a relationship between the two variables, however, this is what I have been...
  13. B

    Min Plane Height to Drop Bomb in Hollow: 335m

    A plane is flying 80km/h in horizontal direction and it has to drop a bomb into 30m wide and 30m deep hollow. What is the smallest possible height for the plane to fly above hollow if the bomb successfully hits the bottom? I made a mistake somewhere but not sure where... the correct result is...
  14. H

    How to calculate water pressure drop in cooling tower piping system?

    When calculating water pressure drop in chilled water pipisystem (closed circuit) we always use Hazen Williams equation as follow:- but in case of calculating water pressure drop in cooling tower piping system (open circuit), shall we modify something in Hazen Williams equation or shall we use...
  15. S

    Minimizing the voltage drop across a capacitor (solution shown)

    The following is the question and the solution to the question. I understand the solution to the part where you find the Ceq and derive Qeq from the equation Q = Ceq*V. However, I do not understand where V1 = V0-V2 come from. When calculating the minimum voltage, how do you come up with the...
  16. Borek

    I Second Tonga shockwave - why a drop in the pressure?

    I already posted this image in GD as a curiosity, but there is one thing that I don't get. This is pressure recorded by my weather station near Warsaw in Poland after the Tonga eruption (the description says '24 h' but it is wrong, I forgot to modify the script generating the plot). Around 20:05...
  17. 0

    Other Should I Transition from Meteorology to Game Design?

    I was enrolled in meteorology but after so many failures, low grades, I decided to drop out. Some friends of mine who were admitted in the same year as me loved the field so much that they are already doing their PhD, in some cases abroad. For a long time I've been day dreaming about computer...
  18. freddie_mclair

    Scaling pressure drop to other temperatures

    Hi, I have some measurements for pressure drop of Helium at room temperature and I would like to scale it to other temperatures. Taking into account that, i) the flow is turbulent, ii) the pressure drop, ##\Delta p##, happens always in the same piping and iii) there is only variation on the...
  19. D

    Find the pressure drop and power loss of pipe when elevation changes

    Summary:: I can’t get the correct answers, I think I haven’t fully understand the theory behind them The answers are given in the picture
  20. Danimal

    Potential Energy Storage: Investigating the Mechanics of a Heavy Weight Drop

    I read about a proposal for storing potential energy by hoisting heavy weights that can be dropped when needed to generate electric power. So using the numbers from a hydraulic turbine from Hoover dam, how heavy would a hanging weight have to be to generate 178,000 horsepower as it descended...
  21. I

    How to determine the pressure drop in pipe diameter sizing

    Hi all, I'm a tinkerer with no formal engineering background, but enjoy read about physics and engineering in general. I'm reading up on fluid flow and I'm a bit grasping at the concepts. As far as I understand it, flow rate, pressure drop and pipe size are all interrelated, where one affects...
  22. D

    How Do You Calculate Static Pressure Drop in a Laminar Flow Channel?

    Hallo. Since I'm new in this field, I hope someone can help me. I have a laminar, steady state, incompressible flow in a channel (a fully developed). Geometry of the channel is on the photo. How should I calculate the drop of static pressure across the channel? Since I have Re, I did calculate...
  23. DarkoX

    Advice on pressure drop calculation

    Hello everyone, I would appreciate any help with my task I am struggling to resolve. I need to calculate or simulate pressure drop when got the following parameters: 1. Supply pressure: 45barg. 2. Pipe Length: 80 meters 3. Pipe diameter: OD - 10mm, ID - 8mm. 4. Pipe material: stainless steel...
  24. M

    Crust on old Battery -- What happens when you drop Vinegar on it?

    I had an old Duracell battery with the bottom covered by a whitish encrustation. When I dropped some vinegar on this, there was a vigorous fizzing, and the encrustation disappeared. Any idea what the encrustation was (presumably soething alkaline, since vinegar is acidic) and what the likely...
  25. H

    Calculating Velocity in the Millikan Oil Drop Experiment

    Hi, I try to find the velocity for a oil drop. I found the forces. ##F=ma => m\frac{dv}{dt} = \frac{4\pi a^3(\rho - \rho_1)g}{3} - 6\pi n a v## with v on the right side, I don't see how to get the solution. I found the solution on few websites, but without the path to find the solution from...
  26. Truman I

    Potential Drop Across 15-mH Inductor at t=0?

    At t=0, I believe that the current is instantaneously 0 Amps. If that is correct, then technically at that instant there is no voltage drop across any of the resistors due to Ohm's Law. So I replaced the resistors with wire. Next, I tried replacing all of the capacitors with open circuits to...
  27. binbagsss

    Drop out of PhD in fluid mechanics and switch to Mres in mathematical physics?

    A post doc in an area that differs from my PhD? I am currently doing a PhD in fluid mechanics but want to do mathematical physics tbh. In another thread I got an answer about a user who had done a PhD in accelerator physics and went to do a post-doc in condensed matter, vice versa even, but in...
  28. L

    What Are the Results of the Millikan Oil Drop Experiment?

    mass: 1.57x10^-19 kg voltages: 400, 457, 384, 369, 400, 355, 369, 436, 384, 369 distance: 0.1m gravity: 9.81 m/s^2
  29. shk

    Force and motion -- A water drop on the windscreen of a car

    Hi Please help me with part C. I have answered the question and have attached it for you to see.
  30. PhysicsTest

    Why is the Voltage Drop Across a Resistor -Ve to +Ve?

    Really very elementary one, if i refer the circuit below For the source in the direction of current the polarity is -Ve to +Ve that is understood which is conventional current, but in the case of resistance in the direction of current the voltage V_R polarity is -Ve to +Ve. Why for resistance...
  31. A

    Light refracting and reflecting in a drop of water to form a rainbow

    I drew the red and green tangent lines and I found that the angles in blue are equal to theta 1. Also , as the BCD triangle is equilateral, theta 2 = 30. With this I can calculate the side of this equilateral triangle as a function of the radius R of the circumference. After that, I can't go on...
  32. iVenky

    When a bird flaps it's wings up, doesn't the pressure drop below?

    I am trying to understand how birds fly. If you consider a plane, using it's engine & streamline shape of the wings, it can create a low pressure region above the wings and high pressure region below and this makes it fly and the upward force is proportional to the speed. Birds seem to flap its...
  33. Kaushik

    Does potential drop when a charge flows through a wire w/ 0 resistance?

    Let us connect a battery of potential difference V to a wire. There is no resistance. Nothing! Now the battery creates some potential difference and the charges in the conducting wire move due to the Electric field created in the conductor by the battery. So, as the charge moves, its potential...
  34. AdrianRodz1

    Voltage drop in a PCB power plane

    I'm trying to maintain a spec requirement of less than 3% drop from farthest pin to closest pin from source. I'used the entire layer for copper but my oart does not require such a large pour accept to handle high current. So I'm considering there's a trade off that should meet inthe middle of...
  35. J

    In an LC circuit the current does no drop to 0

    in an LC circuit the current does no drop to 0 but varies sinusoidally. The capacitor is recharged with a different polarization. Why is this so?
  36. E

    Drop in intensity when light is focused to a point (telescope mirror)

    The parabolic mirror pictured below is such that all incident rays, neglecting diffraction, are reflected towards a focus. A question states that the light cannot be focused to a point precisely, since there exists a circular diffraction pattern in the focal plane. The following diagram is...
  37. M

    Oscillation frequency of 2D circular drop in an ambient environment

    Hi PF! Do you know what the natural oscillating frequencies are for a 2D circular drop of liquid in an ambient environment (negligible effects)? Prosperetti 1979 predicts the frequencies for both a spherical drop and bubble here at equations 5b and 6b. There must be a simpler circular 2D...
  38. Vivek98phyboy

    Excess pressure inside a Liquid drop

    While studying about the effects of surface tension i came across the excess pressure inside a liquid drop. Here they considered a hemisphere ABCDE from the drop and listed out the conditions for it to be in equilibrium. The forces acting on them are taken as F1= 2πRS F2= P1×(Projection...
  39. Tryhard314

    Voltage drop across a capacitor and resistor in series

    In this circuit a battery,Capacitor,and a resistance are in series. For simplicity assume that there is a +4V in the positive terminal of the battery and -4V in the negative one and let A be the capacitor plate connected to the positive terminal and B the capacitor plate connected to the...
  40. H

    Courses Dropping Physics? Should I Retake or Push Through?

    I'm currently taking introductory physics along with a few other classes, and doing well in all of them except physics. We just received our second tests graded, and it's not looking good for me. I did terrible, and I talked with my professor after class about my chances if I stayed. I would...
  41. R

    Pressure drop due to holes in a pipeline?

    We have a project that relating with pipeline system and pressure control, the project is actually having goal to knowing how much pressure drop will occurs in pipe line system that in initial condition the pressure inside the pipeline staying at steady or constant in particular psi and at the...
  42. A

    How to calculate a pressure drop in a branch of a loop ring pipe

    Good day I'm trying to calculate the pressure drop in each branch of the following loop ring system I used the following formula to find the pressure drop but i seems that it worked only for the ring, and the branch #2 ( the branch in the middle), the solution given by the professor show...
  43. M

    A Sessile drop fluid oscillations and frequencies

    Hi PF! I'm looking at a sessile drop of water in ambient air. The drop is plucked lightly, inducing surface oscillations. The fundamental frequencies ##\lambda_i## can be computed from spectral theory, and output complex values, say ##\lambda_1 = 2+7i##. Now, I simulate the experiment via CFD...
  44. M

    Engineering Calculating Voltage Drop Across Non-Ideal Diodes

    So I have this circuit up above and I need to find the voltages across each of the diodes. The only info given is that they are identical silicon diodes at T = 300K. My first thought was that since the diodes are opposite, D2 would be in reverse bias and would act as an open. However, I realized...
  45. S

    Huge pressure drop after changing pipe length (Don't think it's loss)

    Hi All, Recently, I have been struggling to seek a solution for a seemingly simple flow question and try to rationalize my thoughts with mechanical engineering knowledge I have acquired from school but none of them can make me feel comfortable about answering the phenomenon I encountered in...
  46. L

    An alternative and odd view of Voltage Drop

    I was going over some fundamentals with my son and I was trying to explain 'voltage drop' - To which appears to be some confusion on the net with respect to terminology. Many people are confusing 'voltage applied' and 'voltage dropped'. First I will explain what I taught - Let us look at the...
  47. Bheshaj

    Voltage drop: What do we mean when we say that voltage drops across a resistor?

    What do we mean when we say that voltage drops across a resistor?and what does it mean when we say that a point is at lower potential as compared to some other point?Can we say that potential is potential energy per unit charge?
  48. S

    Velocity, acceleration, jerk, snap, crackle, pop, stop, drop, roll....

    Edit: I see this was discussed in the related thread sorry for a repost. If acceleration causes a change in velocity, and jerk causes a change in acceleration, snap causes a change in jerk, crackle causes a change in snap, pop causes a change in crackle, stop causes a change in pop, drop causes...
  49. Magellanic

    Thermo: Calculating the temperature drop from gas leaving a system

    Hi PF! I have a tricky problem that I'm trying to model, and none of the typical textbook examples cover this--or they only cover it tangentially--so I was hoping to get some insight here. (Couldn't find a "Thermodynamics" section of the forums so if there's a better place to post this, please...
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