Direction Definition and 999 Threads

There is a problem in my Physics textbook which says: Homework Statement "A car runs counter-clockwise in a circular lane of 1 km of diameter, going through the south extreme at 60 km/h on the instant t = 0. From that point onwards, the driver accelerates the car uniformely, reaching 240 km/h...

Homework Statement A 200-loop coil of cross sectional area 8.5 cm2 lies in the plane of the page. An external magnetic field of 0.060 T is directed out of the plane of the page. The external field decreases to 0.020 T in 12 milliseconds. Homework Equations No equation The Attempt at a...

Hi I was looking at the Lorentz transformation and I see that it moves in the x-axis if vt is positive. How can I re-arrange the lorentz transformations in a way that will cause the moving frame of reference to get closer to me. I was trying with x'=gamma(x-vt) but I don't know what x is equal...

Homework Statement A uniform horizontal rod of mass 4 kg and length 500 mm, is hinged at the left hand side and supported at rest by a chain (S) attached 10 cm from the hinge. Calculate the magnitude and direction of the reaction force on the rod at the hinge. State the principle you have...

Homework Statement Two +3.0nC charges are shown in the diagram below which are spaced 10cm apart. What are the strength and direction of the electric field at the position indicated by the dot in the figure (Figure 1) ? What is the electric field in N/C? What is the direction of the electric...

I was watching a video explaining how microwave ovens work when I found that there is a difference between my physics textbook and online images of the electric dipole moment of the water molecule, as well as the one shown in the video. Why do they differ?

I have just started studying vector algebra and i was wondering how is the direction of a vector (or any point object) specified in 3 dimensions. I know how to indicate the direction of a vector in 1 dimension and 2 dimensions. Is the direction of a vector in 3 dimensions stated by using angles...

I would like to know why electric field of EM waves changes it's direction to opposite when hitting a conductor surface. I know that electric field inside a conductor is zero but I am not able to connect these two situations.

Homework Statement Two circular coils of diameter 30.0 cm are parallel to each other and have their centers along the same line L but separated by 22.0 cm. When an experimenter views the coils along L, the coil closer to her carries a clockwise current of 2.50 A. Find the magnitude and sense...

Consider a small rigid spherical particle of radius a, fully immersed in a viscous incompressible Newtonian fluid of shear viscosity η above a hard-wall with stick (no-slip) boundary conditions, located at the plane z = 0. A constant positive (external) torque Tx is applied on the particle. My...

Homework Statement Hi guys, it a very simple question, but it causing me a great deal of confusion. The questions are as follows: So I worked out the ans for one which I have displayed below. But what I don't understand is what they want from the second question. Because the way I see it...

Why is there a need to find unit vector? If we are given a vector we can always find its direction.

Hello, everyone! Now I'm trying to develop 2 wheels robot, which travels along the line simulator. The robot can turn only by increasing velocities of each wheel. The conditions are below: - I know velocities of 2 wheels - I know radius between wheels The task is next: How to find new location...

If a particle is in the state of rest on the ground , and I apply a force such that it produces an acceleration 4.9 ##\frac{m}{s^2}## upward , will it move upward , considering there's gravitational acceleration 9.8 ##\frac{m}{s^2}## in the downward direction, or will it remain at rest?

Homework Statement How do I find the direction of the magnetic field at the points? Homework Equations Ampere's B = (UI) / (2*pi*r)[/B]The Attempt at a Solution I know how the Right hand rule, where your thumb is the direction of the current and your hand wraps the direction of the field...

Homework Statement A block with mass m is revolving with linear speed v1 in a circle of radius r1 on a frictionless horizontal surface. The string is slowly pulled from below until the radius of the circle in which the block is revolving is reduced to r2. (a) Calculate the tension T in the...

I would like to know if their are any materials that would allow light to pass in only one direction, In electricity we have diode, which will allow electricity to pass in only one direction, in optics how do we reflect light from one side and allow light from the other side to pass through?

Homework Statement A spaceship encounters a single plane of charged particles, with the charge per unit area equal to σ. The electric field a short distance above the plane has magnitude _____ and is directed _____ to the plane. a) σ/2∈0, parallel b) σ/2∈0, perpendicular c) σ/∈0, parallel...

I have a good understanding on the hall effect. However, I was told by my tutor that the electric field direction at equilibrium remains pointing in the negative side of the conducting material and the force it generated is canceled out. But further reading online text, the electric field...

Homework Statement [/B] "An airplane is flying on a bearing of 340 degrees at 400mph. A wind is blowing at a bearing of 320 degrees at 30mph. Find ground speed and direction of the plane." Homework Equations vx=vcosϕ vy=vsinϕ The Attempt at a Solution [/B] First, my teacher told us to change...

Homework Statement A biker is 40.0m to the east of a flag in a park, heading south at 10m/s. 30.0 seconds later, the biker is 40.0m north of the flag and heading east at 10.0m/s. For the biker in this 30.0s interval, what are: a) the magnitude and direction of the displacement? b) the magnitude...

Does the momentum always get transferred from lower velocity to higher velocity(may be along a negative velocity gradient.) Consider the collision between 2 bodies M1 and M2,(M1<M2) but both having the same momentum.So M1 will have a higher velocity than M2(V1>V2). Now if the velocities V1 and...

This is a somewhat vague question that stems from the entries in a directional cosine matrix and I believe the answer will either be much simpler or much more complicated than I expect. So consider the transformation of an arbitrary vector, v, in ℝ2 from one frame f = {x1 , x2} to a primed...

For a particle undergoing a constant velocity circular motion. I thought friction always acted in the direction of motion which would be in the tangential direction.

Homework Statement What is the direction of the force F on the -10 nC charge in the figure? Give your answer as an angle measured cw from the +x-axis. Express your answer using two significant figures. Homework Equations ##F = k\frac{Qq}{r^2}## The Attempt at a Solution I started by getting...

Homework Statement I am following the first problem on this online pdf: http://www.ce.udel.edu/courses/CIEG212/Homework_1_2007.pdf Homework Equations Equilibrium equations for forces and moments. The Attempt at a Solution I know how to solve the problem, that part is straight forward. However...

If current flows from + to - for example, which pole has greater potential? I assume the + pole has greater potential, but my teacher says otherwise.

Homework Statement A dipole with charges ±q and separation 2a is located a distance x from a point charge +Q, oriented as shown in the figure. Part A: Find an expression for the magnitude of the net force on the dipole in the limit x≫a. Part B: What is the direction of the net force...

Hi. This is from a high school textbook, in a chapter about eddy currents and Lenz's law. In a), a magnetic field is turned on, in b) it's turned off, which both induces a current in a suspended aluminium ring: I think the direction of the current is wrong in both pictures. Any opinions?

Homework Statement A homogeneous semicircular disc of mass m and the radius r is released from rest in the vertical position shown in the figure. Determine a minimum value of the coefficient of friction μ between the disc and the horizontal surface that prevents sliding in the initial moment...

Is the direction of electric field save as the direction of (conventional) current?

Homework Statement Homework Equations The Attempt at a Solution So I began by subtracting. (205-160)=55 i (495+128)=623 j Both of these vectors are in the positive direction. So if I divide the vector by its magnitude I should get an answer of 1 in the positive direction for both i and...

Homework Statement In the figure in the picture uploaded assume that the switch has been closed for a long time such that the inductor acts like a short circuit. Through which resistors does the current pass through and why?? Homework Equations A short circuit is basically a wire or a zero...

I am a physics novice but I recently became a little confused about the direction of a force matters in terms of impact with another object This probably a poor example but let's say in the first case a human body is still relative to the Earth and the bullet is traveling at 2,00 feet per...

This question pertains to the classic ladder-leaning-against frictionless wall scenario. The system is in static equilibrium. The ladder is thin and can be assumed to be made of a homogeneous material so that the center-of-mass lies at the geometric center. The forces in this scenario is...

Homework Statement $$ U_t+U_x+\frac{1}{x} = 0\\ U(x,0)=\phi(x) $$ Homework EquationsThe Attempt at a Solution I learned somewhat of an algorithm for method of characteristics. It works for a different problem : $$U_t + U_x - KU = 0 \\ U(x,0)= \phi(x) \\$$ Method : $$ x_s = 1\\ t_s = 1\\...

Hello, I'm going through Kirchoff's second law, and stumbled across this example on this page: In the image above, you can see that the blue arrows (both arrow 1 and arrow 2) indicate the direction that the current goes in. However, I am wondering why the current cannot go as per the red...

A cylinder rolls on a horizontal, flat surface without sliding towards the left, so it must be rolling anticlockwise about its center of mass (CM). Suppose it slows down to a stop due to friction. What is the direction of the friction at the point of contact? Since it slows down, friction must...

I've been reading that Voyager 2 is scheduled to pass by Sirius in about 300,000 years. Other sources state it is destined to orbit the Milky Way for billions of years. I don't understand how it can be headed toward a specific direction and orbiting the center of the galaxy at the same time.

Homework Statement In which direction would the electric field in the wire point if the wire were pulled to the right? Homework Equations Right hand rule F=qvXB The Attempt at a Solution My answer is downward. I am confused whether I should take the moving charges as positive or negative...

a bowl is filled with tap water .electric current is made to flow due to electrodes attached to rim of bowl(opposite sides of bowl) i have 2 sense pins inserted into the water between the electrodes . how can i convert this analog signal(vd across sense pins) to a digital signal to detect...

We are experiencing a regular series of the Aldebaran occultations by the moon now. I read this in the article http://www.skyandtelescope.com/observing/moon-covers-bright-star-aldebaran/. What puzzle me are the advancing directions of the occultations across the moon described in the article...

I'm having a difficult time trying to discover which academic pathway to pursue. At first, the difficulty came from having broad interests, which I narrowed to a toss-up between space, science and engineering. I found space (astronomy, astrophysics) to be too specialized, physics (pure science)...

Homework Statement In the notes , i noticed that the shear stress on the top plane and the front plane will 'meet together' at the edge . I don't understand it why the direction is like that . Homework EquationsThe Attempt at a Solution Is it possible for both the shear stress to become like...

Homework Statement I need help as to how to find the magnitude and direction of the resultant force, and the equilibrant force. Any and all help is greatly appreciate as I'm stressing myself out over it and I'm not sure what to do. Thanks, Jamie. Homework Equations First question...

Homework Statement Homework Equations F= q v x B The Attempt at a Solution [/B] I tried using the right hand rule to find the direction of the force and seeing if the particle curves that way or not but obviously that's wrong

Homework Statement (a) Determine the current in each branch of the circuit. Homework Equations V=IR Summation of the voltages in a loop = 0 The Attempt at a Solution I have this problem figured out in general, but the only thing confusing me is the current in the middle. What exactly...

Hi, I feel I have solved this problem correctly (solving for vo(t)), however since the current is going in the ccw direction, would this make the current -5cos(10t - 45) versus 5 cos(10t -45)? This may be a simple question, so I am just making sure. Thanks!

Sorry in this question i have several things to ask 1.why can't the E field in the circumferential direction? 2.How can i find the direction of B field 3.according to the formula of curl E=-dB/dt and the curlB=u J did they share the same property so that the direction of E is...

What direction would torque be on a trebuchet in motion at the point where the swing arm is parallel to the ground?