Circle Definition and 1000 Threads

Mentor comment: Harmony360 original post violated our rules. The new wording is mine. D H So, why there are 360 degress in a circle?

How could i mathematically proove that I am living on a circle. Almost got it last night , just need an insight to figure out an equation. Ty.

Homework Statement A ball on top of a circle is acted on by a FG. The ball rolls to a certain point on the circle, and detaches. Ffr Is negligable. Given info: Diameter Of the circle, Mass of ball no ffr x = the distance from the balls posistion to the top of the big circle. x is what is...

I'm getting approximations within 5% of the actual values. Does that sound about right?

Homework Statement Write the equation of a circle in complex number notation: The circle through 1, i, and 0. Homework Equations The Attempt at a Solution I know the equation for a circle with complex numbers is of the form |z-a| = r where a is the center point and r is the...

How can I find the radius of a circle by knowing two points and its arc length? Do I have to use a numerical method to solve for a trigonometric equation or is there any algebraic or geometric method?

Homework Statement http://s2.ipicture.ru/uploads/20120107/67Ag24Qb.jpg The attempt at a solution So, i plotted the graphs of the circle and the curve: http://s2.ipicture.ru/uploads/20120107/x32KTV6y.jpg The shaded area is what i need to find. My plan to solve this problem is to find...

Hi there, I am trying to understand calculus as concerns circles and I can clearly see that the integral of a circumference is an area: \int2∏r = ∏r^{2} but what do I get if I integrate the area, I get ∏r^{3}/3 I am confused as to what this shape would be, I kind of was expecting a...

I'm just wondering about using a Mohr's Circle, do I need to use the same scale for the x and y axes, as surely otherwise my choice of scale greatly impacts the results. I am using one to get my principle second moment of areas, Ix and Iy, for an equal L section. Ix and Iy are where the...

Homework Statement A stone dropped into a still pond sends out a circular ripple whose radius increases at a constant rate of 3 ft/s. Does the area also increase at a constant rate? Homework Equations A = ∏r2 The Attempt at a Solution dA/dt = 2∏r(dr/dt) dA/dt = 2∏r(3ft/s) What now?

Homework Statement --SOLVED-- It seems, that you just apply the pythageos thereom to 'A' and 'B' =)--------------- Lets say I have a circle 'A' with radius 6cm, and a circle 'B' with radius 6cm. These two circles would have an area of 113.097cm^2. When both are combined they would have an...

Hey guys, New here. It's been a while since I've done any physics. I've been playing around with some mental work in my head and I am trying to figure out why something doesn't work. I know it shouldn't work, but I can't figure out the why. What I am talking about is utilizing similar charges...

Sorry for my lack of knowledge, I'm in Grade 7 I just learned that Magnets have dipoles--like this: If those dipoles formed a circle, wouldn't it be possible to create perpetual motion?

Homework Statement PICTURE: http://imageshack.us/photo/my-images/21/circls.png/ A Force of gravity acts upon a ball on top a circle. The ball rolls a down the curve of the circle until a CERTAIN POINT. at this CERTAIN POINT the ball detaches from the circle and travels until it his the ground...

This is my first post here and any help is appreciated. I belong to a drag racing forum and this has been a hot topic of discussion. If you have a 4 inch round pipe by 2 inches tall and insert the pipe into a vice and make it oval shaped it would somehow change the volume. Please see...

So I always wondered why you multiply by pi when you're finding an area of a circle, for a rectangle you multiply by length and width, I guess that makes sense... How I see multiplying a length and width is if you have a length of 5 cm and a width of 4 cm, I imagine you just stack 4, 5 cm...

Hi. I want to know the equation to draw a circle that's a bit tilted. Imagine a 3D circle that's parallel with the Y axis. Now I want to take that circle and have its center cross through the origin still, but I want it to be θ degrees titled from the Y Axis. I'm using the following...

Homework Statement A wagon is drawn by a student pulling with a constant force of F Newtons applied at an angle of θ° to the horizontal. If the wagon is drawn in a circle with radius r meters, how much work is done on the wagon? (I don't remember the actual numbers) Homework Equations...

my textbook says: "As a gyroscope precesses, its center off mass moves in a circle with radius r in a horizontal plane. Its vertical component of acceleration is zero so the upward normal force exerted by the pivot must equal mg." Now wouldn't this always be true. I mean if u have a...

Circle Rolling around Rolling Circle (1) Circle 1 rolls around inside of the fixed base circle. Circle 2 rolls around inside of Circle 1.

Homework Statement A wire of resistance 8R is bent in the form of a circle. What is the effective resistance between the ends of a diameter AB? Homework Equations I have attached the image and my attempt to solve it as told by my teacher. Homework Equations The Attempt at...

Ball Rolls off of a circle :O! PROBLEM! So the problem is, a ball at zero velocity begins to roll on a circle. At a certain point the ball and the circle "DISCONNECT". There is a height x from the roof to the point it disconnects. Given Information. Height X, Diameter D of circle, Vi=0...

Homework Statement Suppose a slingshot rotates clockwise along the circle x^2 + y^2 = 9 and the rock is released at the point (2.99,0.77). If the rock travels 200 feet, where does it land? Homework Equations The Attempt at a Solution I think you might have to find the tangent at...

http://www.up98.org/upload/server1/01/z/cllb59cvnwaigmmar6b5.jpeg What is the method of calculating arc length in In the image above . x & y is known Thanks .

I was looking at the equation of a circle in polar coordinates on wikipedia, http://en.wikipedia.org/wiki/Polar_coordinate_system and I understand that a is the radius of the circle, and that (r0, phi) is the center of the circle. But I don't see what the r and theta refer to :(.

Prove that angle WTU is twice as large as angle WOX. Any help would be greatly appreciated.

Homework Statement An aluminum wire is 0.850 m long and has a circular cross section of diameter 0.780 mm. Fixed at the top end, the wire supports a 1.20-kg object that swings in a horizontal circle. Determine the angular velocity required to produce a strain of 1.00  10–3. Homework...

Hi I just want to check that I am doing this math problem correctly. We were given a density function for review for an upcoming math test. We were then asked to find the volume in a circular radius given this density function. I will post the exact problem now then explain the steps I...

Homework Statement Find a vector function that parameterizes a curve C which lies in the plane x-y+z=2 and directly above the circle x2 + (y-1)2 = 9 The Attempt at a SolutionSo, in order to parameterize the circle, I simply use x=cos(t), y = sin(t) with some adjustments. Namely, I let...

Homework Statement Please see below... Homework Equations Please see below... The Attempt at a Solution Hi. This question is on geometry with circle and triangle. I am stuck only on 2 parts of the solution and not the whole solution... Thank you...

Homework Statement Use greens theorem to solve the closed curve line integral: \oint(ydx-xdy) The curve is a circle with its center at origin with a radius of 1. Homework Equations x^2 + y^2 = 1 The Attempt at a Solution Greens theorem states that: Given F=[P,Q]=[y, -x]=yi-xj...

Homework Statement A mass moves in a circular path that has a radius of 24.6cm on a horizontal frictionaless surface. If the centripetal force acting on the mass is 96.5N, what is the kinetic energy of the mass? r=0.246m Fc=96.5N Homework Equations He told us to use these and "play...

Hi, i can not understand how circle has a nontrivial bundle, Möbius bundle. Can you say me what is its transition function on it.

Homework Statement Two equal masses are glued to a massless hoop of radius R that is free to rotate about its center in a vertical plane. The angle between the masses is 2*theta. Find the frequency of small oscillations.Homework Equations \frac{d}{dt} \frac{∂L}{∂\dot{q}}=\frac{∂L}{∂q} The...

There have been a couple of posts over the last few months that posit a relativistic-speed path in a circle around the Earth and I want to make sure I correctly understand the ramifications. It's the twin paradox in a circle. SO ... here's a scenario that I think will solidify it for me: This...

Homework Statement This is me paraphrasing. It's about uniform circular motion. The question involves a pig on a string dangling below a motor. It rotates in a circle below the horizontal. Resolve the tension vector into components. The vertical component of tension is equal to the...

Homework Statement The Attempt at a Solution So my first thought is that the only way to solve this problem is to apply a characterization of a cyclic quadrilateral. We know that the perpendicular bisectors of a cyclic quadrilateral are concurrent. So here's my thoughts: Construct...

We can express any circle in the complex plane as |z-a|=k|z-b| where a and b are distinct complex numbers, k > 0 and k \not= 1. Is there an elegant way of showing this fundamental property of the complex plane to be true?

This is more of a general conceptual question than a specific homework problem. I know how to do these problems, but I'm not understanding part of them. So, with a given stress element, I first look at one specific face, and plot a two-dimensional Mohr's circle. Then, I find the center...

The question is: A circle touches the y-axis at the origin and goes through the point A(8, 0). The point C is on the circumference. Find the greatest possible area of ∆OAC I graphed the above situation, and used the equation A=(1/2)bcsinA, but i couldn't muster up an answer. Your...

Let a circle be given by 2x (x-a) + y(2y-b) = 0; (a≠0, b≠0). Find the condition on a and b if two chords, each bisected by the x-axis, can be drawn to the circle from (a, b/2) My attempt in this question is not quite relevant at this moment. I just found that (a,b/2) will lie on circle and...

Alright, this is a bit of a confusing one for me. The problem: The ultimate objective is to get the coordinates of the points on the edge of the rectangle (labeled: (?,?) ), given the angle, and the height and width of the rectangle. The more I think about this problem, however, the more I...

Homework Statement Find the Lagrangian of a simple pendulum of mass m whose point of support moves uniformly on a vertical circle with constant angular velocity. (So basically there is a circle around the origin that spins with a constant angular velocity and the pendulum is attached to the...

Homework Statement Can someone check if this is right? The time seems okay, but the work I feel is wrong A ball with moment of inertia 0.1kg · m2 is rotating on a table, but friction is slowing it down with constant angular acceleration. The ball is originally spinning at 2π radians per...

Homework Statement 9. A 0.61 kg mass attached to the end of a 0.50 m cord rotates in a vertical circle. The angular speed of the mass at the bottom of the circle is 2π rad/s. The tension in the string at this point is: a. 18 N b. 21 N c. 12 N *d. 54 N Homework Equations W=mg F=ma...

Homework Statement This is part from a larger construction, but I realized if i can construct this, i can do the larger construction. All ofcourse with ruler and compass. I have been given an angle with its bisector and a point on that bisector. I have to construct a circle trough that point...

Homework Statement A light string can support a stationary hanging load of 25.0kg before breaking. An object of mass m = 3.00kg attached to the string rotates on a frictionless, horizontal table in a circle of radius r = 0.800m, and the other end of the string is held fixed. What range of...

Homework Statement Define a relation on R as follows. For a,b ∈ R, a ∼ b if a−b ∈ Z. Prove that this is an equivalence relation. Can you identify the set of equivalence classes with the unit circle in a natural way? Homework Equations The Attempt at a Solution I have already proven that this...

Homework Statement I need to get a tricycle to move around a circle (depending on the angle of the front wheel) in MATLAB (but any mathematical formulae would help). I have the variables: M (x, y, theta) which is the center point between the 2 back wheels and the angle of the tricycle, the...

Homework Statement A metal bar of length l in the figure below has one end attached at a point P to a circle ofradius a < l. Point Q at the other end can slide back and forth along the x–axis. (a) Find x as a function of θ (θ=angle POQ). (b) Assume the lengths are in centimeters and the...