Resistance Definition and 1000 Threads

Homework Statement Homework Equations R ∝ 1/A The Attempt at a Solution Since there are six copper wires and a steel core, I added the resistance of all the wires and the core and divided them by 7, though I don't think my approach is right since the resistance of the copper and steel...

In a common emitter amplifier while analysing its output impedance ..why we consider collector resistance (Rc) in parrallel with output impedance (Ro) of the amplifier...since as they appear in series ..as seen by the KVL equation(which involves Vcc=IcRc+Vce+IeRe)...

I actually have 2 questions that I am getting stuck on around the same point.. Question 1) An arrow with a mass of 80g is fired at an angle of 30 degrees to the horizontal. It strikes a target located 5 m above the firing point and impacts the target traveling at a speed of 20 meters/sec. If...

I'm not sure if this question has already been answered yet. I was curious what factors effect the resistance of electrons moving through a wire? From the formula R = p*(L/A) i see mathematically why but I'm curious to the theoretical. Does an increase in cross sectional area decrease the...

Homework Statement [/B] Explain how the concept of thermal resistance can be used in the analysis of heat transfer problems 2. The attempt at a solution So I'm made a few key points but I am not sure if I have answered the question fully: Thermal resistance is a heat property and a...

Homework Statement Homework EquationsThe Attempt at a Solution [/B] 1. A copper rod, 100 mm long and 2.5mm diameter, has a resistance of 340micro ohms at 15degrees Celsius. If the rod is drawn out into a wire of uniform diameter 0.5mm, calculate its resistance at 60 degrees Celsius. Assume the...

Hello, I am not quite sure how to work out the before and after charging values for resistance and current. This is the circuit I am working with: So, when there is no voltage then the capacitor can be technically not considered as part of the circuit. So for the resistors, would R = 1/R1...

A question in regards to rolling resistance. Am I wrong in thinking that not everything you hit on the road with your tire effects your gas mileage? Don't tires have a tolerance in terms of how much energy they can absorb before it effects your traction, therefore effecting your gas mileage...

Voltage = 9.0 V, Current = 20 mA, Capacitor (C) = 10 microF, Resistance before (too high) [R_A = R_B] = 10 k Ohms. In a a-stable oscillator, calculating the resistance needed for two resistors (R_A = R_B) to discharge and charge a capacitor (C) so that a LED does not blow. Currently my circuit...

Homework Statement A ball (m=0.7kg) is dropped from a height (h=30m). The air resistance force is given by the formula F=kv^2 where k=0.0228 and v is the ball's speed. The ball bounces after a perfectly elastic collision. Calculate the maximum height the ball reaches after the collision...

Homework Statement Assuming R = R' in the network shown above, determine the net resistance between the points a and c. Express your answer as a number times R. b. Assuming R = R', determine the net resistance between the points a and b. c. Now suppose R' = 2.5R, and find the net resistance...

Homework Statement There is an infinite 2D mesh of conducting wire. Resistance between any two consecutive junctions is R. What is the equivalent resistance between any two consecutive junctions? Homework EquationsThe Attempt at a Solution Every junction is connected to four points and one of...

Should not there be R (resistance) instead of I (current)in the last line i.e I ∝ m/a^2

Homework Statement Mass car 1200 kg . power car constant 20kw . Resistance car motion 500N. Car passes point X and Y with speeds 10 m/s ,25 m/s. Car takes 30.5 s to travel from X to Y 1. Find acc of car at x 2.considering work/energy find distance XYHomework EquationsThe Attempt at a Solution

Homework Statement We have a resistor of 350 Ohm, an inductor of 0.15H and a capacitor of 10 microfarad, connected in series to an AC source of voltage 240 V and frequency 50 Hz. The measured effective voltage over the resistor is 180V, and over the system of the both the inductor and the...

Homework Statement Eight lights are connected in parallel to a 110-V source by two long leads of total resistance 1.6 Ω. a. If 302 mA flows through each bulb, what is the resistance of each? b. What percent of the total power is wasted in the leads? Homework Equations V=I P=V^2/R R. The...

Homework Statement a. What is the net resistance of the circuit connected to the battery in the figure above? Each resistor has the same resistance R. Give your answer as a number times R b. What is the net resistance if the diagonal resistor between nodes A and B is replaced by a...

Suppose I have a tungsten filament lamp with a resistance 0,32 ohm If it operates on 220V line, its power is P=V^2/R=151250W ! However, If the problem is given like , "you have a 100W with resistance 0,32 ohm what's the current? that'd come up as I=Sqroot(P/R)=17,6A First result doesn't make...

Could you solve this?

Homework Statement I am working on a little project in which I analyze a video I found online and try to determine if it is real of a hoax. The video I am analyzing includes a man throwing a football off of a football stadium (at the very top) and making it into a basketball hoop at field...

We Know that in conductive Solids there are lots of free electrons available & they drift when electric field is applied. Their drift velocity is in the range of mm/sec to cm/sec. Now if we consider any conductive liquid which is flowing & we connect the electrodes in such fashion that the flow...

I just did a thermoelectric generator from seebeck plate. And when temperature increases, the plate's resistance increases from 12 ohms to 8 M ohms. Why is that and how todeal with it??

Here is the problem: I have already lost the ability to get the correct answer for AI Homework Statement (a) What is the maximum potential difference that can be applied to the terminals a and b? 33.541 Which resistor will have the largest current? V (b) For the voltage determined in part...

Homework Statement When a nonideal battery is connected to a 3.0-Ω resistor in a circuit, the current in the circuit is 2.0A . When the same battery is connected to a 1.0-Ω resistor in a circuit, the current in the circuit is 3.0 A. What is the internal resistance of the battery? What is the...

The cell can provide conatant emf ε and initial charge of capacitor is zero. Now current through resistor initially is zero and increases. But the potential difference across the capacitor is always a constant with magnitude ε. then ##\frac{q(t)}{C}=E## So ##q(t)=CE## which implies q is constant...

Homework Statement Homework Equations R = pL/A The Attempt at a Solution R(a) = 2x10^-4(0.15)/[pi(0.0005/2)^2] = 152.789 [Ohms] It is slightly off. Is there a subtle point that I've missed? Thank you very much.

>Two wires of the same material are both connected to a 9-V ideal battery. They have the same cross section area but wire 2 is twice longer than wire 1. Compare the following quantities by answering if the quantity for wire 1 is smaller, equal or greater than the same quantity in wire 2. > -...

Homework Statement A 250 gram rock is thrown with a speed of 30.0 m/s. It has a speed of 22.5 m/s just before it strikes the ground. Determine the work done by air resistance. There is also a diagram which yields more information. The rocks path is horizontal and it strikes the corner of a...

Alloys have higher resistivity than pure metals. In real life, our voltage source ,i.e. battery, is constant. Using the formula H=V^2/R, we get that resistance is inversely proportional to heat. Alloys, in that case, will produce less heat as their resitivities are low, so are their resistances.

Homework Statement Calculate Rs so that the draincurrent ID = 4 mA. Vad does the gain A become? uo/ui? For the transistor: k = 3 mA/V^2 Vt = -2 V also: R1 = 50 k ohm Rd = 2.2 k ohm C = infinity for signalfrequencies image of circuit...

Homework Statement What is the equivalent resistance between points a and b in the Figure shown. Homework Equations Equivalent of two resistors (e.g R1 and R2)= R1*R2/(R1+R2) Equivalent of two resistors (e.g R3 and R4) = R3+R4 The Attempt at a Solution Step 1: 6, 12 and 4 ohm resistors...

Last night I watched a good documentary on Netflix Instant called "Resistance". It discusses the issue of antibiotics in human medicine and agriculture. Lots of interesting history with debate about how we've badly mishandled antibiotics. Some heart breaking stories of people who caught an...

Hi there, I'm recently doing research on thermal transport in constriction geometries, and want to get the diffusive constriction resistance for two planar films but with rectangular cross section. I have searched for many literature, but all of them are talking about the planar films with...

Homework Statement I'm currently in computer programming class, and I've finished a project and want to improve on it. We had to figure out how to calculate the gravitational acceleration and time traveled of a projectile to hit a target. I'd like to add horizontal variables in my code, like...

The terminal voltage and current are measured as the resistance is decresed through a cell with emf and internal resistance. Graph of V (y axis) I (x axis) shows straight line decreasing gradient. 1. Explain why terminal pd decreases as the current increases. is terminal pd the same as...

If we connect a single resistor in the circuit of ideal voltage source then what'll be its total resistance? ? Isn't it zero? As shown in image .so is it possible that the total resistance of a circuit is 0 Although it has 5ohm resistor!?

Homework Statement A length of wire, length l, is clamped at its midpoint. It is then stretched on the right side, with the left side unchanged, to a length of l (the right side has a length l). The original Resistance of the wire was R, what is the new resistance of the wire? Homework...

If a field line is moved into a superconductor it meets resistance. This resistance is modeled by adding an image flux thread outside the superconductor which then attracts the flux thread being moved into the superconductor. Why is this attractive force an accurate model of the resistance a...

hi guys i know the title... (sigh not again) and this may be the case but i was hoping one you you clever guys on here could help me to the most apporpriate answer is not. thanks basically we know from skydiving and motorsports if the center of aerodynamic pressure is not equal to the center of...

Homework Statement Estimate the resistance of a gold (wedding-type) ring. State clearly all assumptions, and introduce any equations you use. your solution should also include a brief summary of how you approached and solved the problem. Helpful tip: You will have to make certain...

Hi there! Just say I have large square piece of some homogeneous resistive material like graphite. How would I go about determining the resistance between any two given points? Further, just say I supply a voltage across two arbitrary points, can I determine the voltage difference between any...

a while ago someone posted a fun question calculate the resistance from two points on a grid of resistors going into infinity, now I know the immediate nodes determine the simple resistances between two points but the hard part is calculating the in-between resistances but if the grid stretches...

Homework Statement Calculate ##R_S## given the expression: $$A_v = - \frac{g_m (R_L || R_D)}{1 + g_m R_S}$$ The parameters ##g_m = 1.292 \frac{mA}{V}##, ##R_L = 180 k \Omega##, ##R_D = 18 k \Omega##, ##A_v = 5 \frac{V}{V}##. Homework EquationsThe Attempt at a Solution My question is about...

Homework Statement [/B] Homework Equations V=IRThe Attempt at a Solution I said: A>D=F>B=C>G>H=E I assumed higher resistance would lead to higher readings. However here are the answers: H=E>C=B>G>D>F>A Can someone explain to me why this is? As you can see H=E which combined gives a total...

Consider a wire connected to a battery. Now,potential is analogous to the energy of the particles.And potential in a resistor drops because of the friction inside the resistor(considering there is no friction along the wire and outside the resistor).So the friction determines how much energy is...

Hi, I'm having a difficult time understanding how voltage is reduced in a circuit. I know the relationship of V= IR, but I still don't understand. I think part of the reason I do not understand is the wording used, and the other part is from experience. For example if I have a fan that only...

Hi all, So after the wind almost blew me off my bike today, something occurred to me. It goes like this: We all know that if we bike in the same direction as the air does, then we will get a little push and it makes our journey easier. Then suppose we get a little adventurous (reckless people...

So I was doing a circuit with some friends, and the circuit breaks down such that There is what looks like a parallel circuit, with one branch containing just the wire, and the other branch containing a resistor. The answer to the question shows that the electrons will not flow through this...

Homework Statement Determine the inductor current i(t) for both t<0 and t>0 for the circuit shown in the attached document"Circuit 1. Homework EquationsThe Attempt at a Solution Before t=0, i=(25)/(3+2) = 5A After t=0, i(t)=i(0)e^(-t/tow) tow=L/R=4/(6/5) However, the...

Homework Statement In the circuit shown, R1 = 0.810 Ω, R2 = 8.10 Ω, R3 = 81.0 Ω, and R0 = 810 Ω. See attachment Calculate the equivalent resistance of the circuit when a 7.70 V power supply is connected between points A and C. Calculate the current through R0 and R1 Homework...