Center Definition and 1000 Threads

Homework Statement Jane is sitting on a chair with her lower leg at a 40.1° angle with respect to the vertical, as shown. You need to develop a computer model of her leg to assist in some medical research. If you assume that her leg can be modeled as two uniform cylinders, one with mass M1 =...

We are learning about centers of mass now and it made me wonder, does the universe have a center of mass? If so , what is its meaning? Is it place where "big bang" occurred? Also, on a related note, could the fact that the universe is expanding at an accelerated rate be explained by a net...

Homework Statement A body of mass m, moment of inertia I, radius R is rolling (without slipping) upon the action of force F applied in horizontal direction at a distance x above center of mass (com). Prove that acceleration of com (a) = F[(1+(x/R)]/[m(1+(I/mR2)] Homework Equations F -...

Homework Statement Calculate the X_com of the cone of mass M in terms of quantities given in the picture. The density of the cone is uniform. See the attachments for the picture. Homework Equations The Attempt at a Solution When I did it I got X_com = (3L)/2 and I am...

Center of mass --chair and cylinders! Homework Statement Jane is sitting on a chair with her lower left at a 30° angle with respect to the vertical. you need to develop a computer model of her leg to assist in some medical research. if you assume that her leg can be modeled by 2 uniform...

I have an interesting question, that I've been struggling with for a while now, but I'm somehow messing it up. I haven't found anything on the internet (hard to search for something like this) so I'm wondering if any of you know something useful about it, or do better at finding the solution...

Homework Statement having some major derp problems. I can't seem to remember how to find moment of inertia about the COM of and object or even finding the COM for that matter. I need it to solve a Euler Lagrange problem Can someone give me an idea on the integrals to use and in what...

Suppose that a small hole is drilled straight through the center of the earth, thus connecting two antipodal points on its surface. Let a a particle of mass m be dropped at time t = 0 into this hole with initial speed zero. Find the period of the simple harmonic motion exhibited by the particle...

My textbook is giving awfully complicated formulas for centers of mass for actual objects (if they are a system of massive points, that's simpler for me.) Intuitively though, it just seems like it would be a weighted average?? So, If I have a solid metal cube, divided into two halfs...

Homework Statement I'm being given problems regarding the center of mass of a uniformly dense object, and I am told by the textbook to use: \frac{1}{V}\int x dV I have no idea what to do with that. I'm pretty sure I won't be learning anything about multiple variable integrals for two...

Homework Statement http://imageshack.us/photo/my-images/24/wtfdiagram.png/ Homework Equations The Attempt at a Solution I really haven't the slightest clue how to read this diagram. I see nothing resembling a U.

Homework Statement A man with mass m1 = 60 kg stands at the left end of a uniform boat with mass m2 = 169 kg and a length L = 2.7 m. Positive x is pointing to the right. Assume there is no friction or drag between the boat and water. After the man walks to the right edge of the boat, what is...

Now i am suddenly confused with the concept of the center of mass. As we know , nucleus are a system of many-body,composed of nucleons. And their interactions are very complex between nucleons. I want to know, If we can observe a nuclei such as Ne20, how is the motivation of its center of mass?

I'm trying to find the equation for a circle given two points in x, y and the starting angle, arc length, and two points along the circle. I need to find the equation because I need to translate a sprite along the curved path from one point to another. The situation ends up looking like this:A...

Homework Statement A rod of length 36.00 cm has linear density (mass per length) given by λ = 50.0 + 21.5x where x is the distance from one end, and λ is measured in grams/meter. A. Find Total Mass B. Find center of mass from x=0 Homework Equations 1/M(integral)xdm , where M...

than why center is the brightest part of galaxy? shouldn't black hole suck all the light in? and if so, the more close to center of galaxy, the more time flow slower right? ...... English is not my native language, forgive me If I'm wrong in spelling or gamma

Sorry if this is posted in the wrong section I'm trying to find out what would be a good pick point on a steel point instead of just winging it. There are two sections to the steel pole, both combined together to create a total of 78 feet. The first section is 40' and weighs 3,438.004...

[PLAIN]http://www.link-systems.com/sdkhtml/SDK/print/pr9849.gif

Homework Statement A uniformly charged insulating rod of length 14.0 cm is bent into the shape of a semicircle. The rod has a total charge of -7.50\muC. Find (a) the magnitude and (b) the direction of the electric field at O, the center of the semicircle. Homework Equations...

Homework Statement Homework Equations Please see attachment to #3. The Attempt at a Solution Apparently, the answer is Y= 4R/(3*pi). Why?

Homework Statement <a href="http://www.flickr.com/photos/56362284@N04/6149231787/" title="untitled by redmond0991, on Flickr"><img src="http://farm7.static.flickr.com/6065/6149231787_e6230d69ab.jpg" width="407" height="229" alt="untitled"></a>...

Homework Statement A binary star system consists of a star P and a star Q, of mass 4.0 x 10^10 kg and 2.0 x 10^10 kg respectively, separated 6.3 x 10^9 m apart. Star P and Star Q move in circular orbits with their centers at the center of mass which remains at rest. Find the position of...

I have been reading a number of papers on the biomechanics of running and they all talk about the center of mass (COM), but I haven't found any description of how to determine the center of mass. I understand, for instance, that the center of mass moves forward with more forward lean. The...

Given 2 points on a circle, call them A and B. I know the cartesian coordinates of A. I also know the radius of the circle, the slope of the tangent line at A, and the length and direction of the arc between A and B. I don't know the coordiates of the center of the circle. How do I find...

I was thinking that objects like a sphere have a center of mass in the middle of the sphere and also if you were in the middle of the sphere you would feel no gravitational pull in any direction. So then I was wondering if all objects had a zero gravitational pull at their center of mass. But...

Hello All, I am trying to create an experiment to determine the center of mass and inertia tensor of an aribtrary object. This object is small (softball size), and non symmetrical on all axis. I have some thoughts concerning gyroscopes and accelorameters, but am curious to see what thoughts...

Homework Statement So I have a triangle with points: A (4,2,0), B (3,3,0), and C (1,1,3). We are to find the point at which the three medians intersect in i,j,k format. I've found the midpoints of each side but I don't know where to go from there.

As part of a problem I need to find the center of mass of a hollow hemisphere. I did it in the following way. I considered the lower hemisphere ( around negative z axis ) First by definition, the position vector of the center of mass is obtained as \vec{R}=...

http://helios.augustana.edu/~dr/203/probs/Set%201.pdf Scroll down to #11 for a picture. So I kind of understand the math. I am a little confuse though. So why is a divided by sqrt(2)? If this is a vector, then the center is really (a(sqrt(2)))/2 and the x component would be divided by...

Homework Statement A large wedge rests on a horizontal frictionless surface. A block starts from rest and slides down the inclined surface of the wedge, which is rough. During the motion of the block, the center of mass of the block and wedge. a. does not move. b. moves horizontally with...

Homework Statement Calculate the electric field (magnitude & direction) at the center of a square 52.5 cm on a side if one corner is occupied by a = -38.6 µC charge and the other three are occupied by -27.8 µC charges. Homework Equations Enet= E1center + E2center + E3center + E4center...

Homework Statement Design a full-wave regulated power supply using a 5:1 center-tapped transformer and a 7.5 V, 1 W Zener diode. The power supply must provide a constant 7.5 V to a load varying from 120 to 450 . The input voltage is 120 V(rms), 60HZ.Homework Equations The Attempt at a Solution...

Homework Statement The mass of the homogeneous flat plate is 50 kg. Determine the reactions at the supports A and B. I've attached the diagram. The Attempt at a Solution I know I will need to find the center of mass. I don't remember exactly how to do it, but I found the centroid...

i think it should but I am not sure.

"Infinity" at the Center of the Galaxy http://www.sciencedaily.com/releases/2011/07/110719151234.htm http://www.wired.com/wiredscience/2011/07/milky-way-ribbon/ New observations from the Herschel Space Observatory show a bizarre, twisted ring of dense gas at the center of our Milky Way...

Calculating the direction of the "center" of the universe? I've had a theory lingering in my consciousness for a long time. I've wondered about the relevance between the speed of light, red-shift in stars and galaxies and relativity. Although c is a constant, I have read somewhere that...

Am studying electrical engineering, i was wondering about how to initiate research and development in engineering field, and how to select and find the ideas that will be studied and solved. Suppose a study is done, for whom this new technology will be sold and who will save your rights...

Chris McKay told me that they do take grad students, but I can't find any more information on the Internet (the Ames page points to a dead link for the "Graduate Student Researchers Program") - see http://hr.arc.nasa.gov/student/gradfaculty.html

Homework Statement A 1.0 kg rock is suspended by a massless string from one end of a 1.0 m long measuring stick. What is the mass of the measuring stick if it is balanced by a support at the 0.25 m mark? Homework Equations Torque=(distance perpendicular to force from the center of...

This is a pretty tough question for me. I am trying to learn, so please no rude people or trolls please. Here is the problem I was given. A 50 dyne steel rod is fixed at a point 20cm. from the right end. The clamp at this point provides a force of 200 dynes upward. The rod is in equilibrium...

uniformly distributed load on a beam. it has a single simple support at the center of gravity. Beam length L and load distribution w (pounds/inch) How do I find the shear and moment diagrams?

Homework Statement Two identical uniform rectangular flat planks with sides a and b are glued together to form a T-shaped object. Specify the position of the center of mass. State any theorems you use in order to arrive at your conclusion. See the attempted solution for a diagram. :) The...

I have a project to do and I have to make a demonstration about a physics phenomenon. I'n planning on doing a demonstration that explains one or all of Newton's Laws of Motion. I've chosen to do it on the center of gravity, but I want to know if it's related to Newton's 3 Laws of Motion or is it...

As the title. More specifically, with respect to the center of momentum frames massless particles don't have, why not if they still do have relativistic mass? (Bracing for an easy answer to a stupid question...) :redface:

Homework Statement so we have this engineering assignment (high school final year) where we have to design an airplane wing and one of the tasks is to (graphically, not all of us can even differentiate let alone mathematically derive it) identify the center of mass of the wing... now, i know...

I am wondering about the size of the universe. I have read that we can only "see" 13.7 billion light years away in all directions and that we are in the center. To my mind this presents a problem. The problem is what are the odds that we are in the center of the universe? Then again even...

In Boas' book I can read that the definition of center of mass of a body has coordinates x_{CM}= \int x_{CM}dM= \int x dM. Shouldn't it be this same integral but divided by M?! Also, I didn't find the definition of center of mass for particles or any non continuous bodies. I'd be grateful if...

Homework Statement In a plastic film factory, a wide belt of thin plastic material is traveling between two successive rollers with the speed v. In the manufacturing process, the film has accumulated a uniform surface electric charge density σ. What is B near the surface of the belt in...

hey. I used to be quite talented at math, but I've let my talent deteriorate in the ~10 years since my last calculus class. I have a problem which I'm sure I would have devoured easily back in my school days, but am having trouble with now. I am considering two points on a normal (0 to...

Homework Statement 2 stars are separated by a distancce r, one star has mass 2/3M the other has mass 2M (M is a solar mass). The period of revolution is 5 years, calculate r. Homework Equations Fg=(GM1M2)/r^2 The Attempt at a Solution Ok so I know that the binary star...