Direction Definition and 999 Threads

Is the direction of surface tension on the surface of a liquid into the surface or parallel to it along the surface of the liquid? And how? I am confused between both of them because, when we take an example of line on the surface of a liquid, we say that liquid surface is behaving like a...

Why is direction irrelevant when it comes to approaching the speed of light? I speak of the curious effects that follow (time dilation, swell in mass, etc) Intuition tells me that the big bang happened at a single point, therefore it's only logical to travel in the direction of that point if...

When you start going around a loop to try and determine whether to add or subtract each voltage in that loop, how do you decide which? For example see the diagram just above Q7. http://www.facstaff.bucknell.edu/mastascu/eLessonsHTML/Basic/Basic5Kv.html Starting from any point and going...

A charged particle in a magnetic field experiences a magnetic force that is perpendicular to it. But is that the case with magnetic dipoles? There was this section in my textbook describing Torque on a Bar magnet in a uniform magnetic field which states that the magnetic force m.B on one pole...

Hi I have always been very curious if anybody knows why the magnetic force on a moving charged particle in a magnetic field is always perpendicular to the plane containing the magnetic field's vector and the charged particles velocity vector. Any help would be greatly appreciated. Thanks...

In the fig. attached below,a circular bar is subjected to torsion. A point is considered on the surface of the bar(denoted by point 1). The shear stresses are shown . Why don't we take one of the stresses in the radial direction??

A ball is attached with a string on the side. When the string is pulled up, static friction accelerates the ball forward while the tension rotates the ball. When a ball is placed on a incline with friction, is kinetic friction opposing the motion and giving the ball torque while gravity...

An infinitely long straight conductor 'XY' is carrying a current of 5 Ampere. An electron moving with a speed of 10^5 m/s parallel to the conductor in air from A to B. Calculate the magnitude of force experienced by the electron and direction of force. Pls help. Ur help will be greatly...

basically any time i have an arc, i have electrons flowing in the opposite direction to the field gradient. so when the electrons reach the other side, they will be stopped, which will then produce an EM wave. In, class, my professor drew the direction of radiation in a particular direction, but...

Hi guys, It's been 15 years since I played with radios, and I've basically forgotten everything. Do you think I'm on the right track with this problem? Do you have any suggestions for the circuit needed for the generator and/or receiving filter described in the last two paragraphs? Or maybe...

Hi A person standing on a cart throws a ball at an angle to the horizontal Is momentum conserved (i) in x direction if the cart is on a frictionless surface ? (ii) in x direction if cart is on real ground (i.e. with friction) (iii) in y direction My answer is : with a system consisting...

Hi, I am very sorry if I have posted in the wrong forum, I don't know wether to post in classical physics or aerospace engineering. I have been wondering this theoretical thing a lot lately and I can't figure it out, it should have a simple straight answer though so your help is very...

Homework Statement I have an example problem I would like to solve and unsure how to graphically set up the problem. I would like to derive the answer by the component method of deriving vectors instead of law of sines/cosines. An airplane is trying to keep on a due west course towards an...

To add to the oq - Is the "center" of an object an entirely logical construct? I draw a circle, find it's center and mark a point there. This point, no matter how small I mark/draw it takes up space (both physically and visually in my mind). Anything that takes up space has a center point...

An object is an isotropic light emitting source and the object moves very near the speed of light c. I am an observer on a planet without an atmosphere and I see the path of the object as a line that is perpendicular to the normal from the planet's surface where I am standing. Now take a line...

How they know, how to see the spin of electron>?? Without external field applied, there is random dipole in the paramagnet. for diamagnet, without external field , there will be no dipole exist. Thanks.

The below might need lots of corrections/modifications, since spin is a hard concept to grasp and I don't understand it much. We know that: The angular momentum (spin) of a photon does not have an analogy in classical mechanics. however let's use a loose/inaccurate analogy of something that...

Homework Statement Hi Circularly polarized light we can describe by a vector v=(1,\pm i), where the sign on the phase i describes which way the phasor turns (CCW or CW). I am confused about what sign belongs to which direction. Is there a neat way to determine this?

I found that direction of friction on ball rolling to east is towards east. And I Know direction of friction in moving bicycle when it is not paddled is backward on both rear and front wheels. Aren't they contradictory?? Plz help me...

Hey guys! On 3rd July, ~00:10 AM +10:00 GMT I have been watching night sky. Then suddenly, under Arcturus (no idea how much below, but about 7 full moons in a row below it) I saw a dim star which was never there. In a matter of seconds (5-10 seconds) it increased in brightness and became as...

Homework Statement The problem and its solution are attached as TheProblemAndSolution.jpg. Homework Equations *The (“instantaneous”) dust tail is opposite the direction of motion. *The plasma tail is oppositely directed to the star in question (at all times). The Attempt at a Solution...

I have attached a diagram(figure 1(b)) indicating the directions of the cornering force and lateral force when there is sufficient side-slip angle i.e the vehicle moving direction plane and wheel rotation plane are at a big enough angle a.k.a side-slip angle. From my understanding, the...

how the direction of artifical satellites are changing in outer space by controlling from earth? how the reaction force is created at space without any medium .

When a photon is produced when an atom raised to excited state return to ground state it's frequency can be calculated. but can we predict the direction and polarization of that photon.

Assuming there is a time varying magnetic field (B) , how to determine the direction of the induced electric field due to B. and to which parameters does it depend?

Is it possible to measure the direction of a current at current magnitudes this small? Or only its magnitude?

The figure shows a transistor with a bias circuit. If Ic=50IB and if VBE=0.7V, find VCE. My question is: The current through 700Ω resistor is H=[0.7+(51IB(250))]/700, then when KCL is applied at the left hand node, the current flowing through the 3kΩ resistor suppose to be (according to...

Homework Statement Problem 10.36 The bar has cross-sectional areaAand modulus of elasticity E. If an axial force F directed toward the right is applied atC, what is the normal stress in the part of the bar to the left ofC? (Strategy: Drawthe free-body diagram of the entire bar and write the...

Homework Statement A gun fires a shell with the horizontal component of its velocity equal to 200m/s. At the highest point in its flight, the shell explodes into three fragments. Two of these fragments, which have equal mass, fly off with speeds of 300m/s relative to the ground, one along the...

I see a lot of voltage drops being represented as an arrow. Say a voltage of 20V is represented as an arrow from point a to point b. What is the polarity of and b then? Do the arrows to represent voltage usually go from + to - or from - to +? Thanks for your time.

Homework Statement I have two questions. 1) The ends of a length of wire are labeled a and b. If the current i from a to b is negative, are electrons moving toward a or b? 2) We have a circuit element with terminals a and b. The voltage and current from a to b are both positive. If...

Homework Statement A person, traveling eastward at a rate of 4.0 km/hr, observes that the wind seems to blow directly from the north; on doubling his speed the wind appears to come from the northeast; determine the direction of the wind and its velocity. Homework Equations The...

I have found what I think is the correct answer I just want to check an assumption. The magnetic field points in the +ve z-direction. We are given the initial state vector \left| A \right\rangle_{initial}=\frac{1}{5}\left[ \begin{array}{c}3\\4\end{array} \right] Am I right in thinking that...

Using the given information, is it possible to solve the new travel direction of the smiley face? To clarify, I am casting a ray using the Möller–Trumbore ray-triangle intersection algorithm.http://http://en.wikipedia.org/wiki/M%C3%B6ller%E2%80%93Trumbore_intersection_algorithm by casting the...

A softball of mass .4kg is pitched at a speed of 24 m/sec, the batter hits it back directly at the pitcher at a speed of 20 m/s. The bat acts on the ball for .015 secs. A: What is the impulse imparted on the ball? B: What is the average force exerted by the bat on the ball? pi= mv pi=...

Please find attached a schematic showing the relationship between the 4 main components of a automotive driveline. I do not understand the reason for the directions of the torques and angular velocities in the schematic. At first, I thought this had something to do with equations and...

How to determine the direction of emf induced in an alternator without the need to look at the graph. (i.e) using Lenz's Law or Faraday's Laws of determining the direction? Consider for example the instant when B and dA are perpendicular and no flux is present? Thanks for helping!

I'm not a gamer anymore (my xbox broke two years ago and I never replaced it) so I'm a bit out of touch. However I've read a bit about the new xbox one and I have to say I'm distinctly unimpressed by the direction modern consoles are going in. Any thoughts from gamers or otherwise? For me the...

Homework Statement A pilot must travel directly to a town 500 miles away in a directions 20 degrees east of south from her present position. There is a steady 40 mph wind blowing west to east. Her plane's cruising speed through calm air is 95 mph. Using vector, what must be the plane's...

please help! The formula for kinetic friction acting on a sliding body is μkN When the body is sliding with constant velocity down an inclined plane fk=μkN When the body is sliding up the inclined plane(say due to a force acting parallel to the inclined plane) with constant velocity...

1. A package of mass m is dropped vertically onto a horizontal conveyor belt whose speed is v = 1.1 m/s, and the coefficient of kinetic friction between the package and the belt is μk = 0.60. For how much time does the package slide on the belt (until it is at rest relative to the belt)...

If force includes strength/magnitude and direction, then why do we say a Newton or Pound is a unit of force? Isn't it more a unit of the magnitude of force? Please help. Now that i have been thinking about forces always having direction, this is all confusing me. Thanks

In early physics, i learned a force was simply a push or pull, talked about as a number of Newtons or pounds, such as "the force is 5lbs". Then you learn that a force is really a vector quantity, having both the direction and strength/force, so it should be "5lbs to the east or 15lbs...

Assume that a box is motionless and is located on the floor ground (one box's face touches the floor completely). If we apply a force to this box such that the box keeps its motionless state, what we can say about the friction directions of all contact points between the box and the floor? Are...

I read that for a plane wave E, B and k are always perpendicular to each other but then in a TM mode I have electric field in the direction of propagation. This means this TM and TE modes I cannot have in free space? Can I have them in a laser? If I can have some E-field in the direction of...

This might be a bit philosophical, but is this just from experiment? that for a really really smooth surface, people found that the net force on an incline surface is found to be approximately in the direction normal to the incline plane? (approximately because there's no perfectly smooth...

Direction of force acting on a body in uniform circular motion?? Hello Sir/Ma'am I'm a a novice. I joined this forum to clear my doubts and improve my physics. Here is my question.. " We generally say, frictional force always acts in a direction, opposite to the direction of motion of a body...

when we need to find the direction of radial velocity should we move our right hand from the omega (angular frequency) vector to the radius vector ?or opposite ?

Hello everyone, I came across this problem from my Physics textbook. I do not understand why the direction of the axle force is pointing downward. I think the upper part of the disk is exerting a downward force on the pivot (as it is pulled down by the Earth's gravity), and according...

Homework Statement A person moving towards east with a speed 'v' observes the rain to be falling vertically downwards. When he doubles his speed, the rain appears to come at 30° angle with the vertical. Find the actual speed and direction of rain with vertical. Homework Equations...