Angle Definition and 1000 Threads

Homework Statement As shown in the figure below, a cuboid with uniform density is tilted by hand so that one edge remains in contact with a roughly surfaced floor. The angle of tilt, θ , is gradually increased, and when becomes larger than θ0 , the cuboid leaves the fingers and rotates. As...

In one of the experiments I give to my students, they need to set a burning candle at different (fixed) angles. In the past they have taped the candle to a cup and a needle taped to the cup like in the following picture. This is quite inefficient because for the same angle they need to tape and...

Homework Statement A force F is applied to a box of mass M at an angle θ below the horizontal (see figure). The coefficient of static friction between the box and the floor is μs, and the coefficient of kinetic friction between the two surfaces is μk. a) What is the minimum value of F to get...

Homework Statement At a construction site, a small crane is raising two boxes of nails on a plank to the roof. One box has already been opened and is half full, while the other box is new. The boxes, including the nails weigh 10kg and 20kg, respectively, and are the same size. If the...

Question: A kicker on a football team attempts to kick a field goal from 35 yards. The attempt just clears the goal post that is 10 feet high. The football lands 8 feet behind the plane of the goal. What speed and angle was the football initially kicked? (Use acceleration of gravity as 32...

Homework Statement Find the directional derivative using ##f\left(x,y,z\right)=xy+z^2## at the point (4, 2, 1) in the direction of a vector making an angle of ##\frac{3π}{4}## with ##\nabla f(4, 2, 1)##. Homework Equations ##f\left(x,y,z\right)=xy+z^2##The Attempt at a Solution I found the...

Hi, I just want to double check my understanding of Power angle. Say you have a large network, and you have a bus with a small generator and a larger load on it. For power to be going into that bus from the rest of the network there has to be power angle between the bus and a bus(s) which power...

Here is a circle with center $O$ :cool: Its is given that $\angle ABD=50$ & to find the magnitudes of $\angle ACD$ & $\angle ACB$ Now what I know is (Nerd) $\angle ACD=50$ due to the inscribed angle theorem, Can you help me to find the other angle which I don't know how to find ,stating the...

Homework Statement (a) Find the directional derivative of z = x2y at (3,4) in the direction of 3π/4 with the x-axis. Give an exact answer. (b) Find the directional derivative of z = x2y at (3,4) in the direction that makes an angle of 3π/4 with the gradient vector at (3,4). Give an exact...

Homework Statement Here is a picture of the problem https://www.dropbox.com/s/2bps6ga2o4hjpgw/hw4.png?dl=0 For those who don't want to click the link, basically the problem wants me to calculate the surface brightness of a flat surface at any angle if the source function S = B(T), which is a...

Homework Statement FInd the angle theta between AB and AC. a-1.7m, b=1.3m masteringengineering.com says my answer is wrong. I'm not sure of any other way to do the problem. Please advise. Homework Equations A(3, 0, 0) B(0, -.75, 1.3) C(0, 1.7, 1.5) The Attempt at a Solution r(AC)=...

Hello PF's members I know a magnetic field doesn't work on charged particles if magnetic field being perpendicular to the velocity of the particles. also i know magnetic field doesn't work if a charged particle enters with right angle into the field. But suppose that a charged particle like...

Homework Statement Hi all, I have solved these problems just wanted to see if it's all ok problem 1: a trolley starts at the lowest point of a diagonal plane with a 20m/s speed. Its acceleration is 4m/s^2 going downhill, the trolley goes up then slows until it reaches 0 speed and then goes...

Homework Statement The refractive index of diamond is 2.42. A ray of light passing from the inside of a diamond into air makes an angle of incidence of 20 degrees. Find the angle of refraction. Homework Equations n = refractive index aNd = 2.42 (my book said the speed of light in a vacuum and...

Here is the problem: I am sure I can use pythagorean theorem of quadratic equation to solve but to be honest I'm blanking ridiculously. I have tried setting it on a coordinate grid and finding the resultant, but I have had no luck! I know I've done this problem before in high school but I'm...

I'm really lost on this one. I'm really not sure how to get started on this. I started it out as a force problem and solved for ax = g*cos(theta). I then integrated that (treating it like a constant) from zero to D to find my initial velocity at the time the block reaches the edge of the...

Homework Statement [/B] A baseball player hits a ball 200.0m home run. The ball travels at angle of 45° with the horizontal just after being hit. Determine the initial speed. Assume the ball lands the same height it was hit. 2. Homework Equations The Attempt at a Solution I am not sure how...

Homework Statement Given the diagram below, showing the path of a geocentric satellite S flying over a ground station G, find an expression for the geocentric semi-angle ##\phi## in terms of ##\epsilon##, the radius of the Earth ##R_E##, and the height of the orbit ##h##. Homework Equations...

Homework Statement Instructions for finding a buried treasure include the following: Go 65.0 paces at 249deg, turn to 134deg and walk 134 paces, then travel 101 paces at 168deg. The angles are measured counterclockwise from an axis pointing to the east, the +x direction. Determine the resultant...

Homework Statement A uniform bar with length c can slide a cylindrical surface with a radius of r. Determine the maximum angle theta that guarantees the equilibrium of the bar if the friction coefficient at the points of contact is u. Homework Equations Friction force = u*N (where N is the...

Homework Statement Find: The angle between the force vector and the line AO, and the magnitude of the projection of the force along the line AO Homework Equations cos(theta)=(A*B)/(|A|*|B|) The Attempt at a Solution I thought that since I'm given the force F in cartesian form, that I would...

Homework Statement Each one of the force vectors are surrounded with dimensions. But you're not given any angles. How do you solve for the resultant vector like that? Homework Equations Fr = F1 + F2 + F3 The Attempt at a Solution I tried taking the arctan(200/210) on the 435 N vector to...

My textbook (on celestial mechanics) makes a passing reference to position on an ellipse being expressed as: ##r = a(1 - e \cos E)## before moving on to the substance of the chapter. E is the eccentric anomaly, and r is the distance from the focus to the point on the ellipse. I'm trying to...

Dear everyone,Direction Write the vector in component form. v lies in the yz planeplane, has magnitude 2, and makes an angle of 30 degrees with the positive y axis. Work I know that the x component is zero. <0,v1,v2​> Thanks Cbarker1

Looks like this question is going to make a long thread. :) This is what the problem states Using the pair of compass and a straight edge, Then, After That, Thereafter, Thereafter, The question states to mark the point where the tangent and AD produced as 'X'.Now can you help me...

Please show me the relationship that proves how an inclined plane's angle of incline, θ, is equal to the angle used to find the components of gravity force. I know that the angles are the same, but I'd like a way to show it. Thanks!

Hi all Tearing my hair out trying to calculate the Maximum acceptance angle for a problem. Experiment involved shining a laser into a tube of water. I have calculated the angle of refraction based on the average of two critical angles (one known and one measured manually) as 52.49 degrees...

What is the angle of intersection between the two planes in ℝ3 with general equations x-y=5 and y-z=7? I know that the angle between then is equal to cos-1 (u⋅v/||u|| ||v||) but I am stuck on the general equations given, how can I solve when given these ?

If the the question is too small , Please be kind enough to read it from here Question The interior angles of a pentagon add up to 540 degrees. So thinking that this is a regular pentagon with all 5 sides equal an interior would be 108 degrees. And speaking of the square All four sides are...

Homework Statement Calculate the force on the cilinder. You need the angle of the tangent and r. Homework Equations Down under here. The solution for the angle is 30°. But why does the formula I used did not work out? My solution is 40,9°, why isn't this correct for this excercise? The...

Homework Statement Show that the equation of the chord joining the points P(a\cos(\phi), b\sin(\phi)) and Q(a\cos(\theta), b\sin(\theta)) on the ellipse b^2x^2+a^2y^2=a^2b^2 is bx cos\frac{1}{2}(\theta+\phi)+ay\sin\frac{1}{2}(\theta+\phi)=ab\cos\frac{1}{2}(\theta-\phi). Prove that , if the...

Homework Statement Find x[/B] Homework Equations a+b+c=180[/B]The Attempt at a Solution ADB= 65+65+50=180 How do I find x in DBC?

For example, the term angular frequency, it units is radian per second. For phase, it is also measured in radians or degrees, why is that? Why is the math the same when you use angles to describe oscillations?

Homework Statement Find what x is I don't understand what to do with (3x-23). Homework Equations Angles centered at a point: a+b+c+d=360 https://drtayeb.files.wordpress.com/2011/03/igcse-math-extended.pdf (here is a pdf of the textbook, Exercise 4A, 3i.)[/B]The Attempt at a Solution...

Say there are two lines that can be described as y=m1x + c1 and y= m2x + c2; they intercept at the point (x, y). There's a line that will bisect the angle that the two lines form as they intercept and it can be described as y= m3x + c3; this line will also intercept the other two lines at (x...

Why is the term ##(\sin\theta\,\dot{\theta})^2## fourth order in the small ##\theta##, as claimed by the sentence below (5.108)? By small-angle approximation, ##(\sin\theta\,\dot{\theta})^2\approx\theta^2\,\dot{\theta}^2##. For this to be fourth order, it seems like we must have...

Let $\triangle ABC$ be a right-angled triangle with $\angle A = 90^{\circ}$, and $AB < AC$. Let points $D, E, F$ be located on side $BC$ such that $AD$ is the altitude, $AE$ is the internal angle bisector, and $AF$ is the median. Prove that $3AD + AF > 4AE$ My solution. Can you check it is...

Homework Statement I know that an element that is subjected to max shear stress is 45 degree away from position of an element that is subjected to principal stress.I couldn't understand why the θ s= θ p -45 degree? Cant it be θ s= θ p +45 degree ? Homework EquationsThe Attempt at a Solution...

Hi, As told in the problem I drew a figure, Next the magnitude of \angle BHL should be found using trigonometric tables. Can you help me to and find the angle BHL (Smile) Many Thanks (Smile)

Find the value of angle X 'BC & CD pints are on BE side of triangle ABE. Find the Value of angle X' :)

Homework Statement this is actually mohr's circle formula, forget about the theory,let's focus on the mathematics part. I couldn't understand why the tan( 2 θs1) = -(σx -σy) / 2τxy ? 2θs1 is outside the triangle Homework EquationsThe Attempt at a Solution theorically, tan(180-α )= -tan( α ) ...

1. A uniform bar AB of length 3 m and weight 40 N rests in equilibrium with the lower end A on a smooth plane inclined at an angle alpha to the horizontal, where tan alpha = 3/4 and a point C of the rod against a smooth peg. If the rod makes an angle theta with the horizontal, where tan theta =...

Homework Statement A projectile is fired with a velocity of 60 m per second at an angle, theta, from a horizontal ground towards the roof of a tunnel of height 5m. If the projectile just barely touches the roof, determine the a) angle of projection b) time of the flight c) range of the...

Hello everyone, i'm new to the forum so hope it is the right place for my question :) i need to know the angle between two triangular surfaces, the easiest way would be extract the normal for each surface(u,v) and then using the dot product we can easily compute the cosine for the angle I'm...

There are lots of basic explanations on the Internet of the two most famous uncertainty principles, that of momentum-position and Energy-time, but I do not find any basic explanation of the action-angle uncertainty principle. I do not even know what angle (or what operator) is being referred to...

I am looking for sources which describe how to measure the contact angle between immiscible liquids in a tube. The literature seems to be extremely lacking so if anyone has any knowledge I would appreciate the help.

I'm having trouble finding any sources which describe how to accurately measure the contact angle between immiscible liquids in a tube. Any help would be appreciated.

I think this should be equal to the famous precession angle, but with a negative sign: ##d\phi = 6\pi m/r## correct?

I recently decided to take a whack at this problem. Came up with an interesting approach, thought it would make a good conversation topic. Anyone else tried to do this? What were your results?

Homework Statement why the angle of shear stress ( θs) is given by θp - 45 ?? Homework EquationsThe Attempt at a Solution the difference in angle of shear stress and normal stress is90 degree , am i right? why it's negative 45 degree? is it wrong?