Direction Definition and 999 Threads

Homework Statement In a circular region in the plane of paper, a magnetic field is directed out of the page and decreasing. What is the direction of the electric field at a point to the right of the region? Homework Equations Lenz's law The Attempt at a Solution Since the magnetic field is...

Hey guys, Background: I'm having trouble determining the direction of a current in a wire in response to changing magentic flux. Although I understand which direction of the magnetic field should be for the induced current given the magnetic flux scenarios, I am having trouble determining...

Spin is an operator with components (Sx,Sy,Sz) but do these represent "spatial" components. The question arose because the spin of an electron sets up an angular momentum L = -e/m * S (S and L are vectors) So inverting the spatial coordinate system and requiring that the physical result must...

Homework Statement Three ions, each with a charge Q = e, located at the corners of an equilateral triangle with side length r midpoint of one of the sides of the triangle described M. a) Calculate the magnitude and direction of the electric field E of the three ions generated at point M...

Hi all, Thank you in advance for your responses. I recently graduated with my bachelors in Chemistry (December) and was gainfully employed immediately thereafter (Early January) by company X. I am seeking advice as to the order in which I should pursue certifications and post Bachelor degrees...

Homework Statement You are walking on the graph of ##f(x,y) = y cos(\pi x) - x cos(\pi y) + 10##, standing at the point ##(2,1,13)##. Find an x, y-direction you should walk into stay at the same level.Homework Equations ##D_u f = \nabla \cdot \textbf{u}##The Attempt at a Solution The...

Homework Statement So this is more conceptual than anything. Say there is a wire loop on the x,y axis and a permanent bar magnet above it on the z axis. I understand according to Faraday's law that as the north end of the bar magnet moves towards the loop the magnetic flux is increasing...

Homework Statement I don't quite understand how diode problems can be solved. Whereas having inverse direction of current flow (on paper) when working with resistors didn't matter, working with diodes does. In real life if current flows through diode from - to + on paper it doesn't. I...

Homework Statement If C = A × B, A points up, and B points south, which direction is C? Select one: a. west b. up c. north d. down e. east Homework Equations The Attempt at a Solution i used the right hand rule and got east as the solution could i have a little verification...

I was looking at a few circuit diagrams, and it seems like electrons move in the opposite direction as the electric field and current . Why is this? I don't really understand the intuition behind it.

Hello All! I have a Bio Test on DNA Replication tomorrow and I had a quick question. (I'm in 8th grade) When the textbook states that DNA can only be replicated from the 5' to 3' direction, I don't get it. If it's like this PT. B -> 5' ---------- 3' 3' ---------- 5' <-...

Hello Forum, Let's consider a particle that is giving an initial speed in a certain direction. The particle is now moving in that initial direction at a constant speed. If a later moment a force starts acting on the particle and the force direction is not along the original particle...

A compass is placed near a solenoid. It is closer to the North pole generated by the coil. The magnetic north is 90 deg relative to the compass and the solenoid. The strength of the solenoid is equal to the strength of the magnetic north. In which direction will the compass needle point?

Will you please explain where actually the force due to friction acts while a man is walking forward. I am really confused with a lot of confusing things in the internet. I am unable to give a fixed answer to my students. I saw somewhere that friction acts in forward direction, please...

I am wondering if in a case where the air velocity comes from one face as shown in the picture. Can I assume the whole area going along the channel will be subject to the same convective coefficient? Thanks

Homework Statement A rock is thrown off a 100 m cliff at an angle of 38 degrees below horizontal with an initial velocity of 20.0 m/s. a) What is the total time in flight? b) What is the horizontal range? c) What is the max height reached by the rock? Homework Equations x = x_0 +...

Homework Statement Instructions: You will need to use software for these problems. The goal is to find a number x0 such that the solution to the initial value problem x'=ƒ(t,x) x(0)=x0 passes through the given "target". Attach figures that you used to answer the problems. 1. Consider the...

Homework Statement A long wire carrying 6.50A of current makes two bends. The bent part of the wire passes through a uniform 0.280T magnetic field directed as shown in the figure and confined to a limited region of space. Part A: Find the magnitude of the force that the magnetic field...

Hi. For whatever reason I'm really struggling with figuring out the direction of a moment in two dimensional statics problems. How can I tell if it's CW or CCW? The right hand rule just confuses me even more and I cannot find any explanation that breaks it down simply enough for me to...

Hello, I am afraid this might be a simple question but I am really confused. I am currently working with ferrite core coil antennas, and I am having trouble at understanding their directivity. The cylindrical ferrite core is placed in the middle of the loops. What I have read is that...

Homework Statement If a small positive and negative charge are created at rest at a point between electrodes as shown in the figure. In which direction will they move if one would neglect gravity? Ignore those weird arrows, those are for later questions. Homework Equations...

Homework Statement If z = east and y = south, then x = ______? Select one: a. east b. up c. south d. north e. down Homework Equations The Attempt at a Solution using the right hand rule the answer i got is south is this correct?

Homework Statement Calculate the magnitude of the electric field E = (-11i^+14j^)N/C ∣∣E⃗ ∣∣ = _______ N/C Calculate the direction (relative to the +x-axis ) of the electric field E = (-11i^+14j^)N/C. θ =_________∘ counterclockwise from the +x-axis Homework Equations...

If the speed at which light waves propagate in vacuum is independent both of the motion of the wave source and of the inertial frame of reference of the observer, why isn't the direction? Shouldn't the light travel directly upward from the point of emission and not diagonally, following the...

The problem is in the paint doc.. My question is why is the base vector aR have a negative sign attached to it?

Homework Statement What are the strength and direction of the electric field at the position indicated by the dot in the figure Figure has been attached with the thread Homework Equations E = kq/r^2 The Attempt at a Solution My Complete Solution has been attached to the thread

Homework Statement A car, initially going east ward, rounds a 90 degree curve and ends up heading southward. If the speedometer reading remains constant, what's the direction of the car's average acceleration. The Attempt at a Solution a = Δv/Δt vi = (c,0) vf = (0,-c) (vf -...

The Law of Conservation of Momentum states that the total linear momentum does not change in any closed system not subject to external forces. However, is it true that the momentum in, say, the x-direction does not change in any closed system not subject to forces in the y-direction? I feel...

Important: Imagine that there is a wire connecting the two magnetic poles, (+,-) so there is an induced current and not only an ems. Homework Statement Hello there! I'm wondering if I can use both of these methods to calculate the direction of the current. The first one is Lenz...

Homework Statement Find direction of force on circular loop http://pokit.org/get/img/b886e52efb703d47d09fa6e781c74461.jpg What would hapend if direction of the current in a straight conductor were different ?Homework Equations ------The Attempt at a Solution...

Homework Statement 10kg block on a inclined plane (32degrees) (frictionless) and an applied force 120N horizontally. What is acceleration? Homework Equations Fnet = ma The Attempt at a Solution mgsin32 = 51.9N (from mg) From applied force, in the same plane, we have xcos32=120...

what will be the direction of current at 'P' point in the transformer?

I'm trying to figure out if there is an deep or simple relationship between the following two facts. (1) A stick, in its own rest frame, makes an angle θ with the x axis. In a frame boosted in the x direction, it makes an angle with the x' axis that is given by \tan\theta'=\gamma\tan\theta...

http://img853.imageshack.us/img853/1150/n5pj.png I a can't seem to find out how to determine the direction the current will flow in... I would really appreciate an explanation. Thanks!

For some reason, I don't understand the direction of larmor precession. Torque is: \mathbf{\Gamma} = \frac{d \mathbf{L}}{d t} = \mathbf{r} \times \mathbf{F} As an example, I understand with a gyroscope, using the right hand rule and with angular momentum in the direction as shown in this...

Q1) What angular velocity would be required for your effective weight at the equator to be third of that the north pole? You may neglect all inertial forces except the centrifugal. I understnad the majority of my books solution which is that: At the equator, the centrifugal force is...

Homework Statement http://puu.sh/5Qrxt.jpg Homework Equations τ = dL/dt The Attempt at a Solution I understand the initial and final angular momentum vectors in the diagram, and the answer seems to make sense. But when I initially solved it my logic was that since the axle...

This isn't a home work, so only I'm posting here When we solve y'=cos(πx) we'll get y=sin(πx)/π +C. But plotting direction field seems little confusing for me Since y' is a function of cosine , the value of y' must be within [-1,1]. If i took y' as 0 and tried to plot it and I'm...

Problem: You can make an electromagnet by wrapping wire around a wire and connecting the ends to a battery. If the battery is connected so that current wraps up in the front and down in the back, which direction will the magnetic field of the nail point? Answer: the magnetic field of the nail...

Homework Statement A wire of negligible resistance is bent into a rectangle as shown in the figure, and a battery and resistor are connected as shown. The right hand side of the circuit extends into a region containing a uniform magnetic field of 38 mT pointing into the page. Find the...

Homework Statement Find the potential difference at point P in the diagram. Homework Equations V=IR ΣiVi=0 ΣIin=ΣIout The Attempt at a Solution I understand that you need to use Kirchoff's circuit laws to find the current and voltage at each resistor, but I can't comprehend how a...

Homework Statement Im doing this practice question and I am to determine the magnetic vector potential A for a cylindrical wire with a uniform current density J. i have already determined B both inside and outside the wire no problem.My issue is in the solution given my professor states that...

Homework Statement I understand how to determine the direction on rectangular surfaces, however when it comes to a cylinder or sphere or, in the case of the problem i am working on now, for a long rod that has been bent around in a circle i.e a a rectangular ring, I don't know what to do.

Hello, I have this matrix element \langle n', l', m'| x |n, l, m \rangle where x=rsin\theta cos\phi in spherical polars Which I write explicitly as: =\int \int \int R_{n', l'} R_{n, l} A_{l', m'} A_{l, m} P^{m'}_{l'} P^{m}_{l} e^{im\phi} e^{-im\phi} rsin\theta cos\phi r^{2} sin \theta d...

Hi, I'm learning vectors and there's two notions which I don't distinguish : Is the orientation of a vector (determined by the angle it has) the same thing as the direction of a vector ? thank you

Homework Statement My question is simple. Homework Equations Why do we not take the direction of secondary wavefronts from the point sources to be going backwards to the original direction of the wave as a whole? The Attempt at a Solution Thanks to you! :D

Homework Statement A forward force on the axle accelerates a rolling wheel on a horizontal surface. If the wheel does not slide the frictional force of the surface on the wheel is: A. zero B. in the forward direction C. in the backward direction D. in the upward direction E. in the downward...

Homework Statement Show that the E and B field of a plane EM wave are both perpendicular to its direction of propagation in a non-dispersive and transparent medium. Homework Equations Maxwell's equatons.The Attempt at a Solution Well, I know how to easily show that E and B fields are...

Hi. I'm really confused in how to find the moment done by force. I want to find the moment done by the force in this figure. The book has resolved the force into its components using principle of moments. So, how do i find the moments of the components of the force? I know I'm...

Dear friends, and science lovers, I am doing some statics problems with moment( cross-product).And I've been having some problems solving them.I am getting the result but in opposite sign. I mean I know we have to do R x F , but looks like I am taking R in the wrong a. For example we have to...