Drop Definition and 876 Threads

Hi guys, I'm trying to design circuits that include mostly ohmic devices with the exception of some LEDs. In particular, I'm having trouble coming up with an effective voltage drop across an LED. This is the datasheet for the particular LED that I'm trying to include in the circuit. It has a...

Hi, I understand that for a real transformer there will obviously be a current drop through the transformer due to winding resistance, core losses hysteresis etc. For the sake of power system analysis, however, do you still assume that the secondary and primary voltages are linked by terms of...

I'm a first year graduate student working toward a Physics PhD at a large, top 50, private university in the US. I have weekly (increasingly frequent) panic attacks and I cannot motivate myself to study or do homework. Because of this, I have intense feelings of guilt nearly constantly. I wake...

Hello, Please i have a question.When we have an inductor in a circuit we say that we have 2 electric field : conservative and non-conservative. so who is doing work on the charges?if we draw an rl circuit with a DC source the conservative electric field across the inductor has the same...

Hi, I will keep this short and sweet. I am drop testing an object of complicated geometry froma set height in 10 different orientations. Due to the complexity I decided to make a free falling rig where it slides (via roller bearings for example) when released. Simple freefall analysis...

Homework Statement When an oil drop falls freely, the velocity first increases, but afterwards it quickly reaches a constant speed, since the air resistance becomes equal to the weight of the oil drop. The air resistance is given by: Fair=6\pir\etav, where \eta is the viscosity of air...

Hi, I am working on a project where I am using a LCD voltage display to measure voltage at 2 points in the circuit. The first is the voltage of the batteries providing the power, and the second is to measure the output of the circuit. It is in a very small box and I don't have room for a...

Good afternoon, I am trying to size a reduction orifice for a desired pressure drop. I do not need the drop to be specific, since this is just for valve protection and not for metering. D1 (Pipe) = 2.5" P1 = 125 PSI P2 Required = 75-85 PSI Q = 1020 gal/hr Fluid = Water, 90 Deg F...

In the Millikan oil drop experiment, was the oil particles positively or negatively charged. and what were the charges of the plates. My textbook and what my gr.10 notes say is that the oil droplets and the bottom plate were positive, but every source online says that they were negative and that...

Homework Statement Draw a motion diagram for each motion described below. -Use the particle model -Show and label the velocity vectors 22) Galileo drops a ball from the Leaning tower of Pisa. Consider the ball's motion from the moment it leaves his hand until a microsecond before it hits...

I plotted the distance in cm ( y2-y1) versus the average change in time squared. (This had to be done by hand...) Then I had to find the slope and the y-intercept. Then I was asked to, " ... From your slope, find the magnitude of the acceleration due to gravity (g)" ... I am really...

I'm kind of confused by this: Suppose a rifle is zeroed in at 800 meters (the bullet hits the line of sight at 800m). This means the bullet must be fired at an upwards angle, the scope stays pointing directly at 800 meters. Crude diagram, line of sight = blue, barrel direction = red...

hi friends, I am confused with incompressible and compressible flow.Can i use moody diagram for air compressor.How can i calculate pressure drop in pipe.

Hi, I've gotten a little confused and would like some guidance and confirmation, I've designed an H-Bridge inverter which should output 100A at 20Vrms onto a 200mΩ load. The current target output peak voltage (with max duty cycle of 98% considered) is 28.86V. The LC filter is made up of a...

I want to calculate the vibrational energy of vibrating water drops. To start with I assume water is inviscid. The frequency spectrum can be found in for example Landau and Lifshitz. But I would like to know the vibrational energy of each mode. How should I proceed? Would it be correct to...

Hello, everyone. I've had many of my questions answered by these forums before but this one was a little specific so I decided to make an account here. I am a third year physics major with a chemistry minor. I enjoy chemistry and feel that it can help me down the road. As far as my university...

First of all, I want to say that I am totally ignorant about physics. And I do not understand the general concepts of physics at all. Now coming to the question. Suppose, you drop a green tennis ball from above. Now It usually lands on Earth and stop there ( ignore the bounces for...

Hi, This is not really homework but since it's homework style, I'll post it here and maybe benefit someone else. Homework Statement I need to calculate the final voltage on Bus 2 (labeled B2 in attached PDF). I am trying to do this using per units and my attempt is attached. The...

Homework Statement A circuit contains a 100Ω resistor, a .0500H inductor, a .400μF capacitor, and a source of time-varying emf connected in series. The time-varying emf is 50.0 V at a frequency of 2000 Hz. a) Determine the current in the circuit. b) Determine the voltage drop across...

Homework Statement Find Vad and VebHomework Equations voltage drop, KVLThe Attempt at a Solution I actually did: Vad -24V - 4V + 6V = -22V but this is wrong.I know going the other way Vad: 6V + 8V + 12V = 26V, because it is only drop, and plus to minus on drops means they are...

Hello. When you have a plot of the cross section in function of the centre of mass energy of an e+e- -> hadrons collision, you get a graph with a few peaks which are due to the resonances (ρ, ω, J/ψ...). But I don't understand why at a resonance, the cross section goes up? Or other way...

Hi Why is there a voltage drop in a wire when there is a high current flowing ?. Is this due to the electrons colliding with the lattice which causes the kinetic energy that the electrons have gained trough the voltage to be transfer to heat energy ?

Need some help here! My plant just installed a water scrubber for controlling methanol emissions. Results obtained from stack tests have consistently shown the flow rate of the gasses from the scrubber outlet is about 30% of gas flow rate into the scrubber. From process knowledge, most of the...

Hi; When we go to market to buy tools especially spanners, there are two types of such tools available, Chrome Vanadium and Drop Forged. These letters are punched on them. Please reply as; • What does there means “Chrome Vanadium” and “Drop Forged”? • Which tool is better from both of them?

A typical silicon diode has potential difference of 0.7V when forward biased, to what kind of energy is the (0.7V)*(I)*(\Deltat) converted? thermal energy only? isn't there potential energy through the electric field in the pn junction?

Homework Statement Your data center has 100,000 CPUs. Each burns 100 W at 120 V. Copper has a resistivity of 1.7E-8 Ω*m. What is the maximum length of copper wire on the power supply to give a voltage drop of no more than 1V? Homework Equations P = V*I R = (rho*L)/A, where L is the...

I'm curious the amount the voltage would drop across a resisitor. If you know the power going into the resistor and the maximum voltage allowed is say, 50V. How would that resistor effect the voltage? I understand the voltage would decrease, and when substituting and solving equations the new...

Good evening every one, first post in this forum and only an amateur astronomer here so please be kind. My question relates to the observable black drop effect, when watching the transit of Venus, at first when i looked up what might cause this effect the answer seamed to simply to be poor...

Homework Statement Determine the voltage V0 in the following network if the impedance Z contains: a. a 0.5 mH inductor b.a 10 μF inductor Homework Equations Voltage division for 2 series resistors: (v in)(resistor/total series resistance) ZL = ωLj Zc = -1j/ωC Z = ZL + ZC + R Zmagnitude =...

I am having a problem with an air pressure drop. I have a supply of 100psi of around 4scfm. I have it regulated down to 90psi, but when I turn on an air turbine motor my regulated pressure drops momentarily (1-2sec) down to 80psi. This drop in pressure is unacceptable to other components in my...

What is the reason for the potential drop when current flows through a resistor? Is it due to conversion of potential energy of the electrons into thermal energy while flowing through the resistor?

Forward biased "ideal" diode=>no voltage drop? Does a forward biased ideal diode have no voltage drop?

Forgot to Drop a Class... I went to a CC (two actually, at the same time), and I had signed up for an online English class, and had thought I dropped it, and I apparently didn't. I've got no idea, I'm going to have to talk to a counselor on Monday, since that is the last day of classes (grades...

Homework Statement Hi, I had to calculate the charge of an oil drop using a lab simulation Homework Equations q = mgd/v The Attempt at a Solution This is the result i came up with: The charges are not multiple of 1.6x10^-19 C. How can i fix this? Thanks

How it's going to happen: - 1 container with 3 eggs in it (they must be placed individually in ziplock bags) - Small to medium sized eggs - 3 back to back drops from 75m - Get all 3 eggs out within 20 seconds - The lighter the container WITH the eggs the better Restrictions: - No side...

Hi guys, So textbooks have it that: "Two Lagrangians differing by a total time-derivative of a function of the coordinates are equivalent". I have no idea what that means or how to use it; so I don't know which terms I can drop from Lagrangians, which is a bit of a problem. For example...

Homework Statement Use superposition to find V0 in the circuit: http://imageshack.us/a/img62/5567/eecircfinal1.jpg Homework Equations V = IR Voltage division for 2 series resistors: V across a resistor = (Resistor / total series resistance)(V in) Current division for...

Stop the presses! I've just come up with the perfect solution to the classic engineering challenge of dropping an egg from some hideous height and having it survive. Nothing that I've seen in any rules precludes it, and I can't believe that nobody has done it (or at least wasn't publicized as...

Hello, My physics class is doing the classic egg drop experiment, but with a different twist. We are asked to find the length of the bungee cord needed given a mass and a height to drop it from. The success of the lab is determined by how close we can get to the ground without touching. We...

Hello, I am having conceptual difficulties trying to understand how voltage is dropped across a resistor. The whole idea of it is confusing to me, where does this voltage go? Could it be explained in terms of point charges and electric fields, which is how I am able to visualize potential...

I found this clip pretty educational and interesting. It shows the structural failure of a so-called Prince Rupert's Drop filmed at 130 000 fps (I had not heard about that concept before). Seeing the structure break down from the tail to the head at high speed is pretty amazing, I think :smile...

im trying to calculate the drop force of falling object. we do drop test at my work and believe the figures are wrong. we drop a 24.75lb weight from different heigths to check parts . they have it now set that dropping the given weight from 1 ft only produces 24.75 ft/lb force and they add 24.75...

Homework Statement I have to make an egg drop device. I was fishing for ideas. It needs to be the fastest time and survive the fall. If I win I get 4 points E.C.. Homework Equations Impulse = Ft Position function for falling object s(t) = -16t^2 +Vo + So s'(t) = -32t F = ma p =...

Homework Statement Please look at the attachment for the circuit. The question is this: The switch has been closed for a long time. It is then opened. How long does it take for the potential across the 4μF capacitor to fall to half of its initial value? Homework Equations V =...

Hello, As a charge traverses through a resistive circuit element it will have a certain amount of potential energy before entering the circuit element; and as it passes through, it's potential energy will decrease (due to it converting to kinetic energy, and collisions)--this I iunderstand...

Hey everyone, This semester I felt like I would be overwhelmed with my courses so I ended up taking a "bird" course as one of the five courses... but ironically it is currently my lowest mark. I am debating dropping it (last day to drop without penalty is in 2 days) but before I do that I...

Hi, I have to make the classic egg drop contraption but we're only allowed to use plastic drinking straws, index cards, and hot glue. the width also has to be smaller than 4x4 inches but it can be as tall as we want it to be (but preferably small) and it has to have a door of some sort...

Firstly, there are lots of ways to word the definition of voltage, but the one that intuitively makes the most sense to me is as follows: "One volt is when: The difference in (electrical potential energy per unit charge (q)) between two places equals one." *per unit charge meaning the...

Homework Statement A cubic polystyrene box contains a litre of water at 90°C. It is 10cm wide and has a wall thickness of of 5mm. Room temperature is 25°C and the conductivity of polystyrene is 0.033W/m°C. What is the rate of temperature drop of the water? Homework Equations P=...

Can anyone explain point 44 of the attached pdf document on surface tension. (Here's the link in case attachment doesn't work: http://www.sakshieducation.com/EAMCET/QR/Physics/Jr%20Phy/12Surface%20tension%20_198-208_.pdf How is the surface tension direction found out? {i know it...