Net Definition and 1000 Threads

I am wondering whether electrons have a net motion against an applied constant electric field in a conductor. Intuition tells me that "of course they should", but so far the math has shown me otherwise. Here are my current thoughts: 1) I cannot rely on the obsolute Drude's model. What's more...

(I hope this post doesn't cross the border into the forbidden realm of quackery and speculation.) I have what seems like a simple question about Special Relativity but I haven’t seen it discussed anywhere, nor has anyone I've asked. Does the nonlinearity of the Lorentz factor provide a way...

Information Given: In the figure, a square of edge length 17.0 cm is formed by four spheres of masses m1 = 4.70 g, m2 = 2.90 g, m3 = 0.800 g, and m4 = 4.70 g. Question: In unit-vector notation, what is the net gravitational force from them on a central sphere with mass m5 = 2.90 g? Attempted...

Net Inlet Pressure Required (NIPR) is an individual pump characteristic, determined by test, of what pressure energy is needed to fill the pump inlet. How to generate the curve of NIPR or how to know NIPR of the pump if I am a pump manufacturer??

Homework Statement Two long wires, one of which has a semicircular bend of radius R, are positioned as shown in the accompanying figure. If both wires carry a current I, how far apart must their parallel sections be so that the net magnetic field at P is zero? Does the current in the straight...

Homework Statement A charge of +2 Q (A)is placed at the origin of a coordinate system and a charge of - Q (B) is placed at a distance d from the origin. How far from the origin must have 3rd charge +Q (C) be placed so that the net force on it is zero Newtons. Homework Equations Fe=kQq/r^2...

Homework Statement Homework Equations ## \vec \tau = \Sigma \vec r_i \times \vec F_i ## The Attempt at a Solution ## \vec \tau = \Sigma \vec r_i \times \vec F_i ## ## \delta W = \Sigma F_i \delta x_i ## Let's take our Cartesian coordinate system such that the axis of rotation...

As I understand it Cosmic rays are mostly protons which have a positive charge. If the overall charge state of the Earth remans neutral is there a similar outflow of positive charge or a source of incoming negative charge? Google wasn't very helpful.

Homework Statement A) Determine the net force on charge 1. B) What is the net electric field acting on charge 1? Homework Equations Fnet Enet The Attempt at a Solution Let North and East be positive. Because of symmetry, F21 = F31 F2 = F3 F2 = (9.0x109)(2.0x10-5(3.0x10-5) / (2.0m)2 F2...

Homework Statement Calculate the net electric field at point A. Homework Equations Enet(total) The Attempt at a Solution [/B] The electric field at point A will due to charge 2 will point towards charge 2 because charge 2 is negative. The electric field at point A will due to charge 1 will...

Homework Statement Examine the charge distribution shown. b) What is the net electric field acting on charge 1? Homework Equations I used the equation E= (kq1/r^2) + (kq2/r^2) The Attempt at a Solution I subbed 9.0 x 10^9 in for k, 3.0 x 10^-5 for both q1 and q2, and 2m for r. My final answer...

Homework Statement Homework Equations ΦE = ∑Q enclosed / ε ∑Q enclosed = λh The Attempt at a Solution ΦE = ∑Q enclosed / ε ∑Q enclosed = λh ΦE = λh / ε

Homework Statement Homework Equations The Attempt at a Solution Here's my work :

Homework Statement Homework Equations n/a The Attempt at a Solution I'm kinda confused on the instructions of this net ionic lab. For this lab, I am suppose to find out how several solutions (6 of them) react with each other to form precipitates. We use some systematic way to test these by...

Homework Statement Calculate the net force acting on the object indicated in the following diagram. Show your work. Homework Equations cosine/sine law The Attempt at a Solution First I subtracted 10N and 8N (since they are forces acting in different directions): -8.0N (S) + 10.0N (S) = 2.0...

Homework Statement Calculate the net force acting on the object in the following diagram: Homework Equations cosine law / sine law ONLY solving using cosine/sine laws. The Attempt at a Solution First using the cosine law to find the magnitude of the net force: c2=a2+b2-2abcosC c2=122+152-2...

Homework Statement The Earth has a mass of 5.98 x 1024 kg and the moon has a mass of 7.35 x 1022 kg. The distance from the centre of the moon to the centre of the Earth is 3.84 x 108 m. A rocket with a total mass of 1200 kg is 3.0 x 108 m from the centre of the Earth and directly in between the...

Frictionless environment. One block moving from left to right hits another block and their combined weight equals .5 kg. When the blocks collide they become attached by an adhesive. The second block is attached to a horizontal spring attached to a stationary wall. k of spring is 50 Newtons per...

Hello everyone! I was given the following three questions in my homework, and I had a lot of trouble with them, so I was hoping someone could look them over! If you could just check out my pictures and say "yeah its awesome!" or "nope... [insert helpful answer here]" that would be GREAT. Thanks...

Gotta give the marketing heads some credit on this one. Pretty funny stuff.

Homework Statement Homework Equations The Attempt at a Solution I do not understand why is mgh2 is being subtracted from the overall equation instead of added. I am able to construct each of the work components but when building the overall equation I'm having a problem of understanding...

I am taking an online course on Analytics Modeling from Georgia Tech. The introductory section included a link to a list of core Netiquette Rules, which I find pretty useful.

Hello I am not sure about what should be the best format for a input text file. I think before start shooting in the dark, it's better to ask experienced people. The (C++) program has to create a net. The nodes will be defined in a input text file. For convenience, the net will be a bunch of...

Hello, Could someone please help me with the problem I've typed below? It is very similar to another problem on this forum <http://mathhelpboards.com/pre-algebra-algebra-2/investment-problem-8808.html>. I've tried to solve it in a similar way (exclusion and/or substitution) but I keep getting...

Homework Statement [/B] A fuel gas consists of 75% butane (C4H10), 10% propane (C3H8) and 15% butene (C4H8) by volume. It is to be fed to the combustion chamber in 10% excess air at 25°C, where it is completely burnt to carbon dioxide and water. The flue gases produced are to be used to...

Homework Statement The power driving the railroad engine is switched off. The engine stops, from its speed of 16m/s^-1, without braking in a distance of 1.1km. A student hypothesis that the horizontal resistive force is constant. Based on the hypothesis, calculate the mass of the railway...

Could someone explain how to find the net force of an object based on a diagram. For example a 2 people walking with forces labeled weight force, reactant force, thrust and drag on one image all forces are balanced which I know the net force would be zero however on the second image thrust is...

Homework Statement https://imgur.com/HR8ssJq https://i.imgur.com/ZxAZ5NR.jpg (full problem, #93) Homework EquationsThe Attempt at a Solution Look at the diagram with Fg, Fn, and Fb. Then look two blocks above it, with the summation sin(theta)Fg - Fbcos(theta) This makes no sense to me. How is...

Why do charges outside the surface contribute 0 net flux? The book I'm reading says it's because the flux entering the surface cancels out with the flux exiting the surface. But that means E dot Area must be exactly the same magnitude when entering and exiting to cancel out. But we know E-field...

Homework Statement Homework Equations \overrightarrow{F} = \frac{1}{4\pi\epsilon_0}\frac{qQ}{r^2}\hat{r} The Attempt at a Solution I found to hard summarizing all forces directly adding each to other. The solution of this problem is only matter of drawing the 13-sided polygon and forces...

1. Johns Inc.has just ended the calendar year making a sale in the amount of \$10,000 of merchandise purchased during the year at a total cost of \$7,000. Although the firm paid in full the merchandise during the year. it has yet to collect at year end from the customer. The net profit and cash...

I understand why when deriving the formulas for cars on banked curves, the net force in the Y direction is zero. However, when I google how to derive them, people say that there is a net force greater than zero in the X direction. This is not what my professor says in his explanations however...

Hello Everyone, Question about the centripetal force: the centripetal force is the name given to the component of the net force acting on the object in a direction perpendicular to the object's trajectory and directed towards the center of the osculating circle. This net force component causes...

Homework Statement Two systems that have the same heat capacity Cv but different initial temperatures T1 and T2 (with T2 > T1) are placed in thermal contact with each other for a brief time, so that some heat flows but the temperature of neither system changes appreciably. Show that there is a...

Homework Statement Homework Equations in photos The Attempt at a Solution [/B] First approach: Second approach: The two approaches used net force and net moment respectively in order to find reaction force of O, yet they got different answers. Why? Thank you very much!

I am looking at an Energy Balance equation (see images) for latent and sensible heat. However, I don't understand the terms 'advection of latent heat' Alat and 'advection of sensible heat' Ah. They positively enter the system, but how do they differ from latent and sensible heat itself?

Homework Statement Homework Equations F= (k*q*Q)/r^2 The Attempt at a Solution The answer key gives the answer as D. I thought it was C. If the net electric force acting on P is zero, doesn't that mean that the force between Q1 and P and the force between Q2 and P need to cancel each other...

Homework Statement Homework Equations F= maThe Attempt at a Solution For 8, I think the parachute causes Al and Betty to stop accelerating, so they both have the same net force. (Answer A) F= ma F=m*0=0 F=3m*0=0 For 9, I feel like Al should experience more air resistance than Betty to make...

My book says: "Let us derive an expression for the potential energy associated with an object at a given location above the surface of earth. Consider an external agent lifting an object of mass ##m## from an initial height ##y_{i}##above the ground to a final height ##y_{f}##. We assume the...

Homework Statement In the 3rd pictures , it's stated that q ( flow rate) = vA = kiA , so , i = hydraulic gradiene = difference in head between 2 points/ length . But , i am not sure why A ( area) is given by $$l_1$$ , $$l_2$$ and $$l_3$$ only ? Homework EquationsThe Attempt at a Solution I...

Homework Statement Point charges ##q_1=50 \mu C## and ##q_1=-25 \mu C## are placed 1.0 m apart. Where must a third charge ##q_3=20 \mu C## be placed so that the net force on it is zero? Homework Equations $$\vec F=\frac{1}{4\pi {\varepsilon}_0}\frac{|q_1q_2|}{r^2}\hat r$$ The Attempt at a...

This is a more general and probably silly question, but if you have a ball in your hand and you move it upwards, the acceleration will be positive then after you move it at constant velocity, acceleration will be 0. However, how is net force is 0 when the ball is still moving? You are clearly...

If we have a circle rotating then a force v^2/r is produced but no net directional force exists as it cancels. But if the wheel was not uniform in mass ie not rotating around its centre of mass AND the speed changes over time as a function of the "wheel"'s rotation angle could a net force be...

Homework Statement Three charged metal spheres are arrayed in the xy plane so that they form an eqilateral triangle. What is the net electrostatic force on the sphere at the origin? http://imgur.com/a/4XnoO (sorry I forgot to put this but the angles are 90 for each vertex, which should be...

Net Neutrality is being overturned as ISP telecoms claim they need to throttle bandwidth and speed as too many customers want to stream HD videos and play HD online games. EM waves are fast and unlimited, so is Tiered Premium Billing absurd? ISP telecom expenses include transmitters...

Homework Statement A charge Q is fixed at the centre of a train track, radius R. An electric dipole with charges Q, -Q, separated by distance d. Show that the net force on the dipole is given by F = Q2d/(4πε0R3) b) What direction is this force? c) What is the torque on the dipole? Homework...

1. The problem is attached in a picture. I've done it five times and keep getting it wrong. The correct answer is also displayed in the picture. Thank you for any help. 2. Fg=Gm_1m_2/r^2 3. I calculated Fg between AB and BC (they are equal). So Fg=(6.67*10^-11)(4)(4)/(.10)^2=1.067*10^-10...

Homework Statement What is the net heat flow of an aluminum disk (emissivity = 0.05) with radius 10 cm and temperature 293K placed inside a room where the temperature is 300K? Asurface = π*r2 = 0.01π m2 Homework Equations Hnet = A*e*σ(Tradiate4-Tabsorb4) The Attempt at a Solution By simply...

I am trying to understand the basics of bldc motor. My question is if i am driving the 3 phase motor with sinusoidal waveform. The magnetic field is produced for each phase or it will add together to generate net magnetic field? How to get the net magnetic field.

Homework Statement [/B] A butterfly net hangs from a circular loop of diameter 400 mm . You hold the loop horizontally in a region where the electric field is 150 N/C downward, as shown in (Figure 1) . What is the electric flux through the net? Homework Equations k = 9E9 N E = kq/r2 Flux = Q...