Direction Definition and 999 Threads

Homework Statement Homework Equations F = E x q The Attempt at a Solution I was told the direction of the E field should be pointing upwards but I have no clue as to why. I found the Force = 0.0012 N but not the direction.

Homework Statement Calculate the magnitude and direction of the electric force if a charge of −3.5 × 10−7 C is placed in a field of 12 N/C Homework Equations e = Fe/q The Attempt at a Solution I just plugged in values into the equations to find Fe and my answer was negative so the force is...

Homework Statement Planning a new stunt where he will be shout out of a cannon into the back of a speeding utility vehicle the sit slopes downhill at 10 degrees and the cannon will launch him at 35Km/Hr at and angle of 30 degrees as shown in the attached picture Homework Equations I cannot...

Hello everyone, Can anyone assist me with the following; I have derived some very interesting cosmological quantities within regard to radiation as it moves through space. I am looking for someone trustworthy who can help me verify my work and point me in the right direction without claiming...

Homework Statement A pilot with an airspeed of 500 km / hr wants to fly from City A to City B (which is exactly 700km North of City A); however, there is a wind from the West at 50 km / hr. In which direction should the plane fly in order to arrive directly at it's destination. Homework...

Hi everyone! I just wonder when I use a laser pointer to other direction. How come our eyes able to see it? Since the light is traveling towards the other direction and not to our eyes. Is there an equation associated with that or its just basic logic is needed to understand why this happen. Skyte

This is more of a user experience question. I'm starting to remake a game (see http://playclassicsnake.com/play ) that works on mobile just as well as desktop. On desktop, one controls the snake (the lime green links) with the arrow keys, but I need a different way to do it on mobile. I tried...

Hello! :o I want to prove the following lemma: $t^n-1$ divides $t^m-1$ in $F[t, t^{-1}]$ if and only if $n$ divides $m$ in $\mathbb{Z}$. I have done the following: $\Leftarrow $ : $n\mid m \Rightarrow n=km, k \in \mathbb{Z}$ $t^n-1=t^{km}-1=(t^m)^k-1=(t^m-1)(t^{m(k-1)}+\dots +1)$ So...

Hi An exercise asks to show $ \int_{a}^{b}f(z) \,dz = -\int_{b}^{a}f(z) \,dz $ I can remember this for real functions, something like $ G(x) = \int_{a}^{b}f(x) \,dx = G(b) - G(a), \therefore \int_{b}^{a}f(x) \,dx = G(a) - G(b) = -\int_{a}^{b}f(x) \,dx $ I have seen 2 approaches, either...

Homework Statement A sailing boat moves at 12ms-1 due North then changing direction to north-west and traveling at a speed of 5.5ms-1 . Determine the magnitude of change in velocity n its direction. Homework EquationsThe Attempt at a Solution

Homework Statement : [/B]I just have a quick question about direction of velocity in solving for energy conservation problems. Since energy has no direction, do different angles ever affect the outcome? Like say in a collision where a truck hits three other vehicles and sends all three in...

When a tree grows even at an angle on a hill side it mostly remains vertical . What is at play here to cause the vertical direction of growth ? Thank you, Pat Hagar

How do you know what direction to make vectors A, B and C face when formulating your equation? I guess its unknowable really isn't it? therefore for the sum of forces in x direction you'd just say C + P + B_x = 0 How about if it is knowable? E.g. if B didn't exist and therefore you'd know C...

Homework Statement I'm right now trying to solve a question concerning the direction of an electron in an electric field. There is the picture I added given and you know that there is a homogeneous electric field. The blue line represents the movement of an electron (there is no movements up...

Hi guys .. Glad to be here in this forum of physcs fans. This is the classical problem of cart HORIZONTALLY pulled by a rope that wraps around a pulley and it's pulled VERTICALLY by say, the same mass as the cart (yeah T1 = T2 horizontal and vertical tensions .. = in MAGNITUDE BUT NOT IN...

Hi,everyone,I just got a deep-thinking question about time. I s time a vector?IF it is,what is the direction of it?My personal view is the direction of time is every direction or no direction(there is no direction in mutil-dimesion of the universe?) or no inclonclusion?

Hi, this problem is making my head ache. Lets say that an object is moving at a decelerating speed(-1m/s) starting on 4m/s towards east and stopped after 4 seconds. (There are no friction.) After 4 seconds, the object would have 0 speed, no direction and 0 velocity etc. Question 1 : Is the...

Homework Statement Thewheel is rotated in the anticlockwise direction...The correct reaction force is drawn using the blue pen . I don't understand why the reaction force isn't directed to the left ? which is drawn using the red colour ? IMO, the red colour should be correct because the...

When a person is running is frictional force forward or backward? I do not have good knowledge of

Homework Statement As you can see , the writer state that the direction of normal reaction force(R) is acted upwards , I have another book state that the normal reaction force (R) is acted downwards , which one is correct ? Homework EquationsThe Attempt at a Solution [/B]

We know that the so-called displacement current is defined as $$i_d=\varepsilon_0 \, \frac{\partial\Phi_e}{\partial t}.$$ Like regular current which is the movement of charges, $i_d$ has a direction, even though it's technically a scalar. How do we find its direction?

Homework Statement Hey everyone! I'm new to these forums so I apologize in advance if I do something wrong! I just had a quick question about the momentum in one direction equation m_1v_1o +/- m_2v_2o = m_1v_1f +/- m_2v_2f; I'm just not sure when I'm supposed to add these values and when I'm...

http://tutorial.math.lamar.edu/Classes/CalcIII/CurlDivergence.aspx In the above link, in the 2nd to last blue box on the page (where it tells how to solve a line integral with respect to a vector field using the curl), it says that the line integral of vector field F with respect to r (with an...

Hi I've been learning about angular momentum and torque, and today I learned that torque actually has a direction that is not simply the direction of rotation. I saw about the right-hand rule to establish which direction the torque is going in. My question is - if an object is rotating, will...

Homework Statement Homework Equations - The Attempt at a Solution When the positive particle enters the electric field it will turn and move toward the negative plate. So a) the displacement vector will change direction until it's directed toward the negative plate, parallel with the...

I'm currently pursuing a career in Automotive engineering in Australia, I'm hoping for some advice such as educational requirements, how to get into automotive engineering through a bachelor or master of mechanical engineering, etc.

Hi all, I want to make sure of a particular information. Length is contracted only in direction of motion. If I am on a spacecraft moving with high speed, I shall see the universe is contracted just in front of me that I am going to, but there would be no contraction If I look to regions that...

nothing in the universe moves without force, so what does makes em waves move through space?

Greetings, PF! I have some questions regarding the problem I attached below. It is some sort of Couette flow variation. It's not homework, I'm just learning the basics of TP on my own. I fully solved the problem with the Navier-Stokes and continuity equations, using some assumptions in order to...

I'm studying for the Physics SAT Subject Test using The Princeton Review (2011-2012). There's this motional EMF problem about a rod sliding to the right along a u-shaped wire in a uniform magnetic field that's going into the page and the current moving counter clockwise. Problem is: I can't...

Homework Statement Use Lenz’s law to answer the following questions con- cerning the direction of induced currents. Express your answers in terms of the letter labels a and b in each part of Figure P31.22. (a) What is the direction of the induced current in the resistor R in Figure P31.22a when...

If drift velocity of electrons changes in AC, how does electricity flow through a circuit to then lose potential energy to the devices in the circuit? Also considering the change in direction, does that mean that the live wire and neutral wire also switch roles in AC mains? I am very confused...

Homework Statement What is E in Magnitude and Direction at the center of the square of (fig. 3-7). Assume that q = 10x10-8 C and a = 5 cm Now I have am not well versed with vectors, I don't like them and they don't like me. I can not figure out the directions the magnitudes move in.Homework...

Homework Statement A mass is at rest on a spring on an inclined plane. Which way would I draw the force of friction on a force diagram? Homework Equations Fnet=0 F=-kx The Attempt at a Solution It could point either up the incline, or down the incline. [/B]

Homework Statement u = velocity B = magnetic flux density Homework Equations ∫ (uxB)⋅dl The Attempt at a Solution From my understanding, the direction of dl depends on the resulting direction of (uxB). How will I know if my dl is in positive or negative?

Homework Statement 2. Homework Equations Elastic collision: KE conserved The Attempt at a Solution I don't think there's really anything to work out...why would the 2M block move right as well?

One thing which puzzles me is why do waves move in a direction? A spring oscillates up and down, but a wave oscillates and moves forwards. Why does it move in the forwards direction and not randomly backwards? Thanks for any answers!

1. Homework Statement I have to minimize the function (x1-1)2+x23+x1x2 by the steepest descent method. The initial point is [1,1]T Homework EquationsThe Attempt at a Solution The gradient of this function is ∇ƒ(x1,x2)=[2(x1-1)-x2 3x22-x1]. This...

Hi guys I'm not sure if this is the right area - this is my first post - but it seems like it fits so My question is, is there a way to get the direction of force on a charged particle from a magnetic field without using the right hand rule? What I'm looking for would be a way to just think...

My question is the following. A ball is initially skidding and eventually starts rolling on a flat plane with friction, and later comes to a halt. Which direction does friction act? (see diagram) If friction acts to the right, then the translational speed will go up, and that's not right...

when a ball is thrown in upward direction --how can it be a negative displacement?

I know that when a spacecraft is in orbit, the direction in which the spacecraft produces thrust affects its orbit. If the thrust is tangent to the orbit, the orbit's shape (eccentricity and size) changes. If the thrust is perpendicular to the orbit, but tangent to the surface of the...

Homework Statement I am to find the reactions of a 3 pin frame. Homework EquationsThe Attempt at a Solution So how do I know which direction to label the horizontal reactions? In the diagram HA and HF are in the same direction, I was under the impression that reactions are opposite to applied...

Homework Statement Earth actually has an electric field of 1.0 x 10^2 N/C at its surface pointing toward the center. (b) Compare Earth's electric field and gravitational field in terms of i) direction ii) shape iii) how it changes as height increases. c) What is the largest mass that can be...

Homework Statement If the magnetic field of a light wave oscillates parallel to a y axis and is given by ##B_y = B_m\ sin(kz- \omega t)##, (a) in what direction does the wave travel and (b) parallel to which axis does the associated electric field oscillate? Homework Equations The Attempt...

A ship sails 130 km due north from island A to island B and then 92 km, in the direction 22° south of east, to island C. The ship after that returns directly to island A. Calculate the magnitude and direction of the displacement vector in the last trip. Draw appropriate diagrams. Homework...

If you remove heat from an exothermic reaction will the equilibrium shift to the products or to the reactants according to le chatelier's principle

Hello , which of the following has the correct T direction?

Homework Statement Two long, straight, parallel wires carry currents that are directed perpendicular to the page as shown in Figure P30.9. Wire 1 carries a current I1 into the page (in the negative z direction) and passesthrough the x-axis at x a. Wire 2 passes through the x-axis at x 5 22a and...

Hi! My question considers no specific problem, but rather different concepts I have trouble getting my head around. So I would be really happy if you could help me understand different kinds of friction, and maybe above all their direction, acting on a rolling object. :) Fist we have kinetic...