Angles Definition and 911 Threads

Whats the relation between degree and time, is there any historical answer.

Homework Statement For the given configuration, the path difference between the 2 rays is given as δ=dsinθ1 - dsinθ2 Homework Equations Small angle approximation? The Attempt at a Solution I'm used to seeing a double-slit situation where only the exit angle is specified, and thus path...

So I was trying to learn how to find the angle between two complex 4-dimentional vectors. I came across this paper, http://arxiv.org/pdf/math/9904077.pdf which I found to be a little confusing and as a result not overly helpful. I was wondering if anyone could help at all? Many thanks in...

Homework Statement Show that the scatter angles of the photon (θ) and electron (Φ) in the Compton effect are related by the relation: ##cot (θ/2 )=(1+\frac{hf}{mοC^2}) tan(Φ) ## Where f is the frequency of incident photon 2. The attempt at a solution I wrote down the equations of conservation...

Because on the book it is said that little angles are vectors but my question is: Are they vectors at all or they are scalar and we assign them a direction by multiplying them by a versor? The same for angular velocity, is it a vector at all or we made it a vector for making the right hand rule...

Given an Isosceles triangle with the area of 100 with internal angles of $$40^o, 70^o,70^o$$ $A=\frac{1}{2}bh$ so $100=\frac{1}{2}\left(z\sin\left({70^O}\right)\right)\left(2z\cos\left({70^o}\right)\right)$ $z$ is length of one the equal sides At least started here

Homework Statement I have 3 masses (Fα, Fβ & Fg) with 2 pulleys, and a wind variable which is in static equilibrium. I have already calculated the appropriate forces for the 3 masses by multiplying it with 9.81m/s² (gravity). Fwind = 60N Fα = 313.9N Fβ = 619N Fg = 882.9N I'm required to find...

I once saw a graph of angle vs time. In order to avoid a big shift in the graph when the angle crossed over from 359 degrees to 1 degree, this graph was circular, with time along the radius of the circle. Is there a name for this type of graph?

So, I'm trying to plot a 3D "dipole" (an arrow with a small torus around it basically) in mathematica, and want to rotate it according to Euler angles... I use this code for the rotation matrix: rot[a, b, g] := RotationMatrix[g, {1, 0, 0}].RotationMatrix[b, {0, 1, 0}].RotationMatrix[a, {0, 0...

Homework Statement A motorised model plane is attached to a light string anchored to a ceiling. The plane follows a circular path of radius 0∙35 m as shown in Figure 2. The plane has a mass of 0∙20 kg and moves with a constant angular velocity of 6∙0 rad s−1 . (a) Calculate the central force...

A man throws a ball horizontally with an initial speed of 20 m/s. Determine the two possible angles theta 1 and theta 2 of release so that the ball strikes point B. The distance between the man and point B is 15 meters. The initial height of the ball is 1.25 meters. Answer: Theta 1 = 5.8...

In most physics introductions Euler angles(pitch, roll, yaw) are defined with respect to Cartesian coordinate system. If I chose not to use a Cartersian coordinate system but instead use a latitude, longitude and a proprietary vertical coordinate(and no back transformations to Cartersian...

I understand that the refractive index of different materials affects the speed of light but does light change speed in glass when entering from air at different angles of incidence?? if not what causes the variation in lateral displacement?

Homework Statement Suppose that in a fixed-target proton-proton collision, the two protons are scattered with equal energies at equal angles θ/2 to the beam. Show that in the CM frame, this implies they are scattered at right angles to the direction of the beam. Calculate the energy and...

I asked my teacher , i didnt get any satisfactory answers , can u tell me why dimensions are always at right angles .

Homework Statement ok so my professor gave me this problem to solve, it goes like this :(I will also have a picture below) In the square (ABCD) is a point P which divides the side BC into 2 halves and point R which divides the side CD into 2 halves The angles at APB and ARB are the same...

I'm having problem understanding why negative angle of cosine is a positive value but negative of sine is a negative sine angle?why is this so?can someone please help me with this confusion? Thanks in advance!COS(-angle)=COS(angle) Sin(-angle)=-Sine(Angle)

Homework Statement A red ball and blue ball are sliding on a frictionless surface, each ball has a mass of 40g. They collide in an elastic collision. Initially the red one is at rest and the blue one is traveling in the x direction with a speed of 4 m/s. After the collision the blue one is...

Homework Statement I have three angles that relate the sensory body frame to the Earth centered Earth fixed frame: roll_ecef, pitch_ecef, yaw_ecef I have the longitude and latitude. Find the roll, pitch and yaw angles that relate the sensor body frame to the local North East Down frame...

I am having my students do a lab to calculate the coefficient of static friction along a ramp. They are calculating the coefficient of static friction between felt and the table to be something like 0.40, yet when i did this lab, but along a horizontal surface, and not with a ramp, i get a...

Homework Statement Suppose that two measurements are made on a qubit in rapid succession. The first is δz and the second is δn. Suppose the first results is always +1. Calculate the probabilities of obtaining the results +/- 1 for the second measurement in terms of the angle θ between z and n...

Hello! This post is strictly related to my previous one. Let's consider the same context and the same image. Regarding the oblique incidence of a wave upon an interface between two dielectric, all the texts and all the lectures write an equation like the following: e^{-j k_1 y \sin \theta_i} +...

Homework Statement A student could either push or pull, at an angle of 30 degrees from the horizontal, a 40kg crate, where the coefficient of kinetic friction is .21. The crate is moved 18m. Calculate the minimum work for pushing and pulling. Homework Equations W=F•(change in)X•cos(angle in...

This is actually for a wood shop project... but it certainly involves geometry! I am trying to build a real-world regular icosahedron. I know I need 20 equilateral triangles for the faces. But I do not know what the angles of the sides/thickness should be, to join those 20 triangles into a 3D...

Please explain it.

Homework Statement This question has popped up recently and I was completely stumped. How to find the angles of a parallelogram given only area and the length of the diagonals? I'm trying to find a generic solution or formula that works for a non-rhombus. Homework EquationsThe Attempt at a...

Hey! :o I am looking at the following exercise: Consider the ellipse $$\frac{x^2}{p^2}+\frac{y^2}{q^2}=1$$ where $p > q > 0$. The eccentricity of the ellipse is $\epsilon =\sqrt{1-\frac{q^2}{p^2}}$ and the points $(\pm \epsilon p, 0)$ on the $x$-axis are called the foci of the ellipse, which...

Homework Statement Consider an inelastic collision between two blocks on a horizontal plane. Block M1 is moving with velocity Vo and collides with block M2 which is at rest. During the collision a fraction Q of the original kinetic energy is lost. It is observed that M1 is deflected by an angle...

Homework Statement I need an equation for a physics project, and I'm not sure which to use. I am given the distance and time variables, however I don't have the angle or altitude they are looking for. Which equation do I need to use? Homework Equations Velocity related equations? fab five...

Hello, Suppose that I have two triangles ##\bigtriangleup ABC## and ##\bigtriangleup XYZ## that are known to be congruent by the side-side-side axiom, from which it follows that the parts are also congruent, such as the angles. My question is, how do I determine which of the three angles of...

hi everybody, I'm looking for tables of k-factor (sheetmetal) for different materials and different angels.

Hi. We can write a polarised photon as ##\left|\alpha\right\rangle=\cos(\alpha)\left|\updownarrow\right\rangle+\sin(\alpha)\left|\leftrightarrow\right\rangle##. Trigonometry gives us $$\left\langle\alpha | \beta\right\rangle=\cos(\alpha)\cos(\beta)+\sin(\alpha)\sin(\beta)=\cos(\alpha-\beta)$$...

△ABC has side lengths 4, 4, and 7. Is there another triangle with the same side lengths but different angles? I get a lot of questions like these, and I don't know how to judge whether or not they are true or false. Drawing them on paper doesn't always help me either, but I do try to - to get a...

I was going through this link -...

Homework Statement A baseball weighing 140g is traveling to the right at 35 m/s, makes contact with a baseball bat, and then leaves the bat at 55 m/s to the left at an angle 25 degrees from the horizontal. I got the right answer, I how how the solution works mathematically. The answer is...

Homework Statement Find the angle of the face diagonals of a (unit) cube. I agree with this solution, but I have a problem with another face diagonal: the face diagonal from the angle (0,0,1),(0,0,0), and (1,1,1). Homework Equations dot product cos-1(a.b/ (|a||b|) The Attempt at a Solution...

How does one prove ##\sin{(x+y)} = \sin{x} \cos{y} + \cos{x} \sin{y}## for all real ##x## and ##y## (not just for ##[0, \frac{\pi}{2}]##? Almost every "geometric proof" I see for formulas like the one I mentioned above, or results such as ##\lim_{x \rightarrow 0} \frac{\sin{x}}{x} = 1##, places...

I recently read that the impact of air resistance on the horizontal range increases as the launch angle increases (http://moodle.davidson.edu/moodle2/pluginfile.php/121168/mod_resource/content/2/Brancozio%20fly-ball%20paper.pdf). A graph depicting this is attached. Is there a reason for why this...

Hello, I'm running a galaxy formation simulation. The output specifies the coordinates in (x, y, z) of all the particles in a galaxy, which usually fall in a disk. The orientation of the disk depends on the initial conditions, but it is generally not aligned with any of the coordinate axes...

We have the following statement by Euclid : "I say further that the angle of the semicircle contained by the straight line BA and the circumference CHA is greater than any acute rectilinear angle, and the remaining angle contained by the circumference CHA and the straight line AE is less than...

Okay, I know I must sound like a complete idiot here, but please bear with me. I've come across a scenario in which I have triangle ECF. Angle ECF = 60 degrees, Angles CEF and CFE are unknown, lengths EC and FC are unknown and equal and length EF is r√3 and not equal to lengths EC and FC I...

I've got my final test in trig coming up, and the one thing that I simply cannot get a handle on are, coterminal angles, specifically ones where you find coterminal angles for a negative angle, in my class they are mostly done in radians. I understand how to get all the angles of a positive...

Homework Statement A 60 kg tight-rope walker carries a long beam with a mass of 30 kg across a 10 m long wire. When she is at the centre of the wire (i.e. 5 m across), each section of the wire makes an angle of 5° to the horizontal. Assuming that the mass of the wire is negligible, calculate...

Homework Statement Say a human is moving through space with constant acceleration due to gravity. There are no external forces/torques on the body other than the force of gravity. The person applies an internal torque at some joint, let's say the knees, so that they bend. Assume the rest of the...

Hi, everybody. Mi name is Fabio Onier Osorio Pelaez and I'm from Colombia. I hope to be finishing my Bachelor´s degree in Physics at University of Antioquia by next August. I'm doing my final project on the detection of planets by the Radial Velocity technique and I have a question about an...

So my math teacher told me that as long as an angle is less than 90 degrees. The sine value of that angle will also be equal to 180 subtracted by that angle. Why is it this way? I just don't understand why it is true spesifically for sine values. Is there are a way to compare this to triangles...

Homework Statement Two pucks are moving on a frictionless air table are about to collide. The 1.5 kg puck is moving directly east at 2.0 m/s. The 4.0 Kg puck is moving directly north at 1.0m/s. What is the total kinetic energy of the two-puck system before the collision? A. Square root of 13 J...

Homework Statement The question says: Find the number of X-M-X angles in MX6, which has an octahedral geometry. Homework Equations None The Attempt at a Solution To do this question , I used p&c . Since there are 6 X in MX6 and we have to choose two of them . Therefore total number of M-X-M...

Hi, I was just wondering if someone could help clarify how pi - theta = phi? That is the link to the youtube video I was watching, the guys pretty good check him out if you want to learn how to derive the differential scattering cross section.

You live in the building on the left in the drawing, and a friend lives in the other building. The two of you are having a discussion about the heights of the buildings, and your friend claims that his building is half again as tall as yours. To resolve the issue you climb to the roof of your...