Circles Definition and 307 Threads

Homework Statement A large circle is inscribed with 3 smaller circles, eachhttps://www.physicsforums.com/newthread.php?do=newthread&f=156 of the four circles is tangent to the other three. If the radius of each of the smaller circles is a, find the area of the largest circle. Homework...

Homework Statement My niece has to write a paragraph on circles and cylinders. This is the exact question: "How are circles and cylinders related? Write a paragraph to explain what you learned about circles and cylinders." Homework Equations The Attempt at a Solution I am...

Hi all, I am not sure if this is the right place to ask but I have two problems which I require enlightenment. The questions are, 1) Show that the intersection of two lines can be computed by rational operations. 2) Show that the intersection of a line and a circle can be computed by...

This might be a bit of a naive question but I am only just starting to learn the very basics of this stuff. I'm hearing about being able to account for the mass of, well, massive particles, by saying that in our cool universe, there is this field pervading all of space that certain...

X = ?

Homework Statement i have a graph or r against V and to make it a straight plot i then plotted ln(r) against V, Homework Equations The Attempt at a Solution the problem is i dnt know how to find the capacitance from the graph. it definitely isn't the gradient or the point of...

I have found an equation which deals with regular polygons touching circles tangentially with each of their sides. P=Dn\tan(\frac{180}{n}) where P is the perimeter of the polygon. D is the diameter of the circle. n is the number of sides on the polygon. i originaly thought it would be...

I came across this question. We're looking for the conctd components of this set of circles: centered at (0,1) and with radius 1-1/n B ((0,1), 1-1/n) for n = 3, ...to infinity The radii are getting larger up to 1. I'm thinking the connectd comp. form an open set at infinity would it be...

Homework Statement F=Force, v=Velocity, a=acceleration m=mass (0.01kg) R=Normal Reaction to surface Hi, can anyone help, I keep getting the wrong answer on this question and it is really annoying me. Here is a picture of the diagram: "A Marble of mass 0.01kg is on top of a smooth...

In certain philosophy discussions the concept of a square circle sometimes comes up as an example of something that can be proven not to exist. It occurred to me that the impossibility of its existence depends on: 1. the definitions one uses for square and circle; and 2. the geometry in...

Hello everyone! I'm trying to find out how to precisely construct three congruent circles inside a larger circle, each tangential to both the outer circle and the other two circles. For example: http://img4.imageshack.us/img4/1044/verybasicdrawing.png An image I found on the internet...

Can someone help me understand why this is the case? I tried forming a cartesian equation for the two circles but there were too many variables that it would be too messy to compute. Otherwise I am rather stuck on how to do it. I would appreciate it if someone can explain how to prove this...

how do you name a circle? Obviously you could name it by its centre example a circle with centre at O would be called circle O. but what if you have two concentric circles?

Dear all, i want to draw the Mhor's circles for various orientation agles on a same axes

Homework Statement Please see the attached figure The radius of the biggest circle is 10. The required is the sum of all circles and the sum of all triangles in the figure. There is an infinite number of circles and triangles. My answers are: for circle: 475/3 pi for triangle: 175/2...

Homework Statement In general how do i parametrize a circle of radius r at centre (a,b,c) laying on a plane? E.g. (x + y + z = 6) Homework Equations The Attempt at a Solution

Does the magnitude of centripetal force as well as the tension change in a vertical circle?

At the top of a circle, does the direction of the contact force depend on whether or not mg is > than or < than the resultant force? So when mg is < than the resultant force, mg is acting downward but there is a greater force than this toward the centre, so to compensate for this the contact...

Homework Statement...

http://arxiv.org/abs/1012.1268 http://arxiv.org/abs/1012.1305 These papers seem to claim that the circles found by Penrose and Gurzadyan in the WMAP data, which were presented as evidence of pre-big bang activity, are entirely consistent with what we would expect the CMB to look like from...

What is the most compact way of arranging 5 circles inside 1 large circle. If possible, show it by drawing a picture.

Homework Statement Three mutually tangent circles with the same radius r enclose a shaded area of 24 square units. Determine the value of r to the nearest unit. Homework Equations do i use the arc length formula to find the answer? [b]3. The Attempt at a Solution A=(central...

Homework Statement The diagram below shows four congruent circles whose centres are the vertices of the square DEFG and whose circumference touch the sides of an isosceles triangle. Area of triangle ABC is 10000 units square. What is the radius of the circles, to the nearest unit...

You guys ever heard of these things? I had no idea. (No they're not hoaxes; they're completely natural.) Here it is in motion:

Hi everyone. Having a circle, knowing its center and radius, how can I calculate the normal vector? I need more information? Moreover, how can I calculate a tangent vector to the circle, knowing its center, radius and the normal vector? If I rotate this circle, it is possible to calculate...

Homework Statement If I spin in circles, in place, am I accelerating? Homework Equations If acceleration is a change in velocity, which is a vector quantity, does only a change in direction count as acceleration? The Attempt at a Solution

Homework Statement Here is the equation of a circle: x^2 + y^2 - 3x + 7y - 6 = 0 It is your job to find the center and the radius of the circle. -------------------------------------------------------------------------------- Enter the coordinates of the center and the radius...

A chord of length 4cm divides a circle of radius 3.3cm into two segments. Find the area of each segment. I've managed to workout the area of one of the segments (approx 1.84 cm^2). This is the correct solution given in my answer booklet. The second segment area would therefore be 2*pi*(3.3)^2...

Geometry Problem Involving Circles and Fixed Radius- Please Help! I have a compass with radius X, and my friend has a compass with radius Y. We both draw a circle with our compasses so that our circles intersect at two points. Call these two points C and D. You draw a common tangent to both...

Homework Statement A member of the family of the circles that cuts all the members of the family of circles x^2 + y^2 + 2gx + c=0 orthogonally, where c is a constant and g is a parameter is? Homework Equations The Attempt at a Solution Let the equation of the required circle...

http://southamnews.org/index.php?option=com_content&view=article&id=885:ufton-crop-circle&catid=1:latest-news&Itemid=1 This one has a very clear picture of it http://www.alien-ufos.com/ufo-alien-discussions/30737-crop-circle-reported-ufton-nr-southam-warwickshire-uk-25th-june.html Last...

Homework Statement Okay. So my goal is to bounce a particle off of 3 circles with centers at the vertices of an equilateral triangle. The side length of each side of the triangle is 6 units and the radius of the circles are 1 unit. I am shooting a particle from anywhere at any angle with unit...

The straight line parallel to each other is parallel. Concentric circles are parallel,too. As shown in figure, There is a big circle,Oa，Another one is small, Oc.They are concentric circles. AB is a straight line. AB and Oa are intersections D, AB and Oc are intersections C. EF is a straight...

Homework Statement I don't know why but my brain is having one of its moments and I can't work through this. Not even on paper anymore. Okay so I have 3 intersecting circles. Like a Venn Diagram. How do I find the area of all three minus the instersecting parts. I know how to do two...

We have a circle of certain radius.How many circles of smaller radius(we are provided with the ratio of radius) can be placed within the larger circle? Help me to determine the least number of the smaller circles that can be filled?? I am trying to generate a generalized solution, and looking...

A. 2 circles that have the same center have their radiuses respectively 5 nd 3 cm. From A which is a point of the big circle are constructet the tangents with the small circles and we mark the pint of tangent A and B. Let's mark D and E the points where these tangents touch the big circle. Find...

i really need help with this proof. suppose two circles intersect at points P and Q. Prove that the line containing the centers of the circles is perpendicular to line segment PQ

Homework Statement A circle has the parametric equations: x=1+2cos\theta y=3+2sin\theta dy/dx= -1/tan\theta Find the tangent equation at the point with parameter \theta Homework Equations y-y1=m(x-x1) The Attempt at a Solution I've tried putting dy/dx in as the gradient and...

Homework Statement Suppose T is a Mobius map take Real -> Real and infinite infinitely to 0 a) What's the image of the family of lines parallel to Real? b) What's the image of the family of lines perpendicular to Real? c) Show the Mobius map take D = {z :|z|<1} onto itself iff Tz =...

1. The base of the yellow triangle has length 8 inches; its height is 10 inches. Each of the circles is tangent to each edge and each other circle that it touches. There are infinitely many circles. The radius of the largest of them is __________ and the total area of all the circles is...

Homework Statement Three concentric circles of radii 1.5m, 2.5m, and 4m are filled with a gas that breaks down in electric fields greater than 1.6 x 10^7 volt/meters. What is the highest potential difference that can be maintained between the innermost circle and the outermost circle. (Hint...

(keep in mind, its circle math.. :/) Write the equation (x+9)2+(y-5)2=12 in general form.

Homework Statement Given a Ferris wheel that rotates 5 times each minute and has a diameter of 19 m, with the acceleration of gravity as 9.8 m/s^2, what is the centripetal acceleration of a rider? Answer in units of m/s^2. (There's a diagram that shows a ferris wheel with radius 9.5 m spinning...

[SIZE="5"]Good day all I have two lists of data A & B. The max & min for A is different from B. I want to draw circles, by specific software, representing each one of the two list of data. The max of both A&B should have the large circle and the min of both of them should have the...

Homework Statement Draw a circle of radius R with the center at the origin. Get the function that represents the top half of the circle. Let d be between 0 and R. State the definite integral that gives this area. Let P be the point were x=d intersects the curve. Let theta be the angle...

Homework Statement The diagram shows a semicircle APB on AB as diameter. The midpoint of AB is O. The point P on the semicircle is such that the area of the sector POB is equal to twice the area of the shade segment. Given that angle POB is \theta radians, show that 3\theta =...

hi everyone ! we have two circles that doesn't have intersections now we want to find a point on each circle that the distance of this two points are 'k' please help me . . .

The Apollonian Packing is generated by starting out with 3 mutually tangent circle and then using descartes theorem to find two other circles that are mutually tangent to each other. This creates 6 curvilinear triangles, and in each, we inscribe a circle tangent to all three of the sides that...

Hey, Given two points, the origin and (a,b) in R^2, I have convinced myself that there are four circles that pass through these points, two circles with larger radius so the arc is "shallower" and two with smaller radii with "longer" arcs joining the points. I am trying to calculate the...

Hi everyone, I'm new and this is my first post here. I'm 37 yo, I'm italian so forgive my english. My question is about the law of relativity that says that an object moving is shorter, when I observe it. The shortening is the famous sqrt(1-square(v/c)). Ok, but now imagine this: I have 2...