Center Definition and 1000 Threads

Homework Statement Find the position of the center of mass for a thin sheet and homogeneous, with sides R and 2R ,from which has been subtracted a half circle of radius R. [Xcm=(2/3)*R*(4-pi)]Homework Equations Rcm=(1/M)*∫rdm The Attempt at a Solution By symmetry we know Ycm=0. For de...

I have a question about a spinning spool, there is a spool spinning and is the sistance traveled by the circumference the same as the center of the circle? You can refer to the diagram attached for a question I had trouble with from a physics olympiad. The answer was (B). Thanks in advance!

Homework Statement Given a homogenous rectangular surface, sides of length a and b=4*a, with a circular hole in x=a and y=a/2, find the center of mass. Homework Equations R=1/M*Ʃmi*ri , M= total mass, r= position vector area of a circle = pi*r2 , r being the radius The...

Homework Statement A mass of 200 kg is hanging directly in the center of a chain; the chain makes a 20o angle from its horizontal. The chain will break if more than 2000 N of force are applied at any point on the chain. Will the chain break?Homework Equations F=ma Tfy=mg(sin\Theta) g=10m/s The...

We all know the proof, from Newtonian mechanics, that the motion of the center of mass of a system of particles can be found by treating the center of mass as a particle with all the external forces acting on it. I want to prove the same think, but within the framework of Lagrangian mechanics...

Hello! I'm here again, now with a new exercise! :biggrin: Homework Statement A block of mass m is at rest over this wedge (it's a triangle) of mass M that is at rest over a table. There is no friction. The point P of the block has a height h from the table. Then the block starts to move. What's...

Homework Statement a toy which have a shape of tank (military vehicle) has a platform of 192mm long, 140mm wide, weight of 2075grams. The canon is 239mm long, 50mm wide, and weight of 400grams. the canon is on top of the platform and being assembled 58mm from the front side of platform. where...

Probably a stupid question as I'm sure we don't but stargazing gets me thinking. The last prevailing theory that I heard of was a massive black hole at the center of the milky way (and all other galaxies). However, the core of the galaxy is the brightest part by far and other than extremely...

Homework Statement I'm trying to understand the equations given in my textbook (Principles of Physics, Ninth International Edition) for finding the center of mass. The equations are given below. They're used to find the x, y, and z components of the center of mass for objects. I'm trying to...

Hi. Just like in classical mechanics, I've read that in relativity, the velocity v of a particle just reverses after an elastic collision in the center of mass. I.e, if v is the velocity before the collison and v' is the velocity after, then v = -v'. I wondered how one goes about showing this...

Homework Statement A trailer with a mass of 900 kg with mass centre (centroid) at G is attached to a towing car at A. If the car and trailer reach a velocity of 60 km/h along a horizontal road in a distance of 30 m from rest with constant acceleration, compute the vertical component of...

I put this under statistics because of your knowledge of the Gaussian. I have run into an elementary problem. I was considering what the average value, <x>, is for a Gaussian with an x offset, and got results which don't make sense to me. First, it is obvious that for P1(x)=e^(-(x^2)) the...

This is actually part of a much bigger goal, but I have isolated the problem I am having, which I have been struggling with for quite a while. I feel like the problem may be obvious to someone here. Homework Statement I attached a diagram of the problem to try to help illustrate it...

I should say that while I've taken some physics courses, I should probably be considered a layman or hack as I haven't done any real world engineering. I'd love to hear some more expert feedback on this topic. I'm sure that there are many approaches to this concept. For this project, my goal...

Homework Statement The problem and cross section are attached. (#2 on the PDF) I have to find the length of b if the shear center is at point O. The horizontal lines that are not labeled are of length a.The Attempt at a Solution I took the Moment about O to get the equation for e. I have...

Hi, this is a problem on center mass. Homework Statement A beam hangs straight down from a point O(O is placed at x=0 and y = 0, aka origo). The beam is attached to the point O. Beam has length L and mass M. The density of the beam is uniform, so the centermass of the beam is...

and successfully fission. let's say a neutron approaches the spherical nucleus from a particular distance. its possible route to the nucleus has a conical shape. how far from the center can it strike and still fission? If it just nicks it just inside a tangent line will it fission?

Calculus 3 project – any and all help is appreciated. We've just gone over center of mass with double integrals, so it's a bit peculiar to see this project feature only one integral. I went over that in calc 2 – and as a result, know how to calculate it that way. However (as you will see in...

I was parking my car into a rather narrow spot and in doing so, scraped just a little paint off of the side. I took it back to the Volkswagen service center and they told me that they won't just patch that small scratch up, but will have to spray paint the entire door so that the door looks...

Hey, I am new to this forum hoping that I can get some help with a project. I also hope to be accepted as a new member, hopefully learning from everyone here. I am sorry to ask a simple question that may be easy. I am learning and experimenting as a hobby, I do not have access to super accurate...

Hello all, Just trying to find a formula and need some help. If a tire is 22 inches in diameter, what are the RPMs of the outer diameter of a 22 inch tire versus the RPMs of the outer diameter of a 2.5 inch center cap, on a car traveling 30 MPH? Are they the same, or are the rotations of the...

Homework Statement If β=0 the neurone model is \dot{u}= -u \dot{v}= v2 + v - u + \delta If \delta = 1/4 it has critical point (0,-1/2) Transform the system so that the critical point is at the origin so let \bar{v} = v +1/2 and find the equations of motion for (u,\bar{v}) Homework...

How to find the center of groups of order 8?

Hi, I have some questions regarding on the locating of the center of gravity. I have read some txtbk regarding on finding the COG for structure/element that is homogeneous. Therefore, the COG will conincide with the centroid of the the volume. Am i right to say that homogeneous...

I have, many times, while I was in college. It was on one of my routes to/from home. http://onetanktrips.wordpress.com/2009/01/29/visit-the-center-of-the-world-right-here-in-ohio/ For a while, there was a "For Sale" sign right behind the road sign, but I never got a picture of the two. :frown:

Homework Statement A carpenter's square has the shape of an L, where d1 = 19.0 cm, d2 = 2.00 cm, d3 = 2.00 cm, d4 = 9.0 cm. Locate its center of gravity. (Take (x, y) = (0, 0) at the intersection of d1 and d4.) Picture ---> http://www.webassign.net/pse/p12-07alt.gif Answer = (____...

Hi, I am having some trouble understanding the formula for the magnetic field for a straight wire. The equation is: B = (μ/4∏)(I/R)(sinθ2 - sinθ1) the picture looks like this: ...___ __| . |____ with the current coming in from the left. To find the magnetic field at the point (middle)...

I'm aware I'm raising a topic which must have been discussed several times, but I couldn't find anything specific to my question. So... Let's assume the universe began from a big bang, which seems for sure. Since then the universe expanded, and it's currently growing. One question, which leaves...

Homework Statement 9) Three cubic boxes, each with side 0.1m, are stacked on top of one another. The lowest one is filled with gold bars and has mass 25kg; the middle one contains aluminum bars and has mass 10kg. The top one contains balsa wood and has mass 2kg. The height above the floor...

Homework Statement The z com of the entire ice cream cone, the base being an inverted right circular cone, the top a hemisphere. Equal density throughout. Must solve using integrals and density relationship. Homework Equations The z com of the top hemisphere (ice cream) is equal to 3/8 R...

Well, I spent literally 45 minutes typing an in-depth post explaining the problem, the variables, and my (probably incorrect) approach only to be logged out and having the post completely lost after pressing the preview button. Sigh... apologies if it's not as thorough now, but I've run out of...

Homework Statement Two objects are on a stick where one is stuck in place and the other one can slide. Both objects have the same mass and the stick has negligible mass. Homework Equations COM = \frac{m_1 x_1 + m_2x_2}{m_1+m_2} v_1 = t The Attempt at a Solution COM =...

Homework Statement Find the center of mass of the lamina which occupies if the density at any point is proportional to the distance from the origin. 36 <= x^2+y^2 <= 81, y >= 0 Homework Equations The Attempt at a Solution Rewrote it in polars to get 6<r<9. The x is clearly 0 as...

Hello, If we know the value of the field variables at the nodes of hexahedral element. How one finds the value at the center of the element. The hexahedral element is trilinear and solved using 2x2x2 gauss quadrature rule.

Homework Statement https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-prn1/553004_1959186995753_1725123128_934768_456680196_n.jpg In case the words are too small: I2= 6.61I1 The net magnetic field at center of loop is 0. I'm looking for the radius of the loop Homework Equations for...

When a bucket of water is at rest the water on the sides will rise for the following reason taken from my textbook: Water tends to cling to the walls of the glass because the adhesive forces between the molecules of water and the glass molecules are greater than the cohesive forces between...

Is it possible to have a center of momentum frame in a system with a photon and a massive particle? If you were to do so in a system with two massive particles, this would involve redefining the velocity of the particles in the CM frame. E.g. if A moves towards B with speed 2v, in the CM...

I was doing some reasearch on electrons, and I found that they have both particle and wave like characteristics. Is this the reason why? because they travel in waves around a nucleus? or am I missing a piece of the puzzel? :smile: Cheers

From what i know there is this Goldilock Zone of the galaxy where is not too much radiation coming from the Super Massive Black Hole at the center of our galaxy and where our solar system is... but in the future, can we venture closer to the center of the galaxy where is no more the galactic...

Problem: A symmetrical rowboat, mass M = 116 kg, length L = 6.89 m, points toward the shore. A man, mass m = 90 kg, stands in the back of the boat, distance d = 35.7 m from the shore. If the man now walks to the front of the boat, how far will he be from the shore? Here is what I did...

Homework Statement The machinist's square shown in the figure consists of a thin, rectangular blade connected to a rectangular handle. Determine the x and y coordinates of the center of gravity. Let the lower corner be x=0, y=0. Homework Equations x_cg = (m_1 * x_1)+(m_2 *...

Homework Statement Find the center of mass of the solid figure similar to a cone pointing upward with slope = 1 Note: the density varies with z^2 and the edge has a slope of 1. From symmetry we see that both Xc and Yc are equal to zero. Find the center of mass in the z direction as a function...

Homework Statement Show that the paraboloidal wave centered at the point z1 is converted by a lens of focal length f into a paraboloidal wave centered about z2 where 1/z1+1/z2 =1/f Homework Equations Equation of paraboloidal wave and transmittance through a thin lens. The Attempt at...

Center of Mass Rowboat Question...Please Help! Can someone please help with below question? I really don't know where to begin... When empty, a 166 kg rowboat is symmetrical. A boy of mass 70.5 kg sits 2.1 m from the center of mass of the rowboat toward the front of the boat, and a girl of...

Homework Statement I have equations that are y1= 2sin(\frac{3}{2}x) and y2= \frac{1}{3}x the point where they intersect is called "a" (about x≈1.88). Find the center of mass where M is the total mass of the object.Homework Equations xcm= \frac{1}{M}∫x dM The Attempt at a Solution I found...

Homework Statement An Object A of mass M falls in a vertical plane under gravity. While it is in air, it breaks into two fragments, one having mass M/3 and the other having a mass of 2M/3. The center of mass of the broken fragments taken together shifts compared to that of the object A...

Homework Statement In the figure (I'll try to find it) a ring of radius .71m carries a charge +580nC uniformly distributed over it. A point charge Q is placed at the center of the ring. The electric field is equal to zero at field point P, which is on the axis of the ring, and 0.73 m from its...

Homework Statement A 58 kg woman and an 78 kg man stand 8.00 m apart on frictionless ice. How far from the woman is their CM? 4.6 m If each holds one end of a rope, and the man pulls on the rope so that he moves 2.6 m, how far from the woman will he be now? Use two significant figures in...

Hi Here is a problem I am trying to do. A point charge q is located at a distance r from the center O of an uncharged conducting spherical layer whose inside and outside radii are equal to R_1 and R_2 respectively. Find the potential at the point O if R_1 < R_2. Now I was thinking of method of...

Is kinetic energy of center of mass of a system is equal to KE of of system?? Does Kinetic energy(KE) of center of mass is equal to kinetic energy of system? I think no... Example take two identical particle moving with velocity v and -v. kinetic energy is mv^2 but KE of center of mass is...