Center of mass Definition and 899 Threads

A 3kg mass is positioned at (0,8) and 1 kg mass is positioned at (12,0). What are the coordinates of a 4 kg mass, which will result int he center of mass of the system of three masses being located at the origin (0,0)? I know that m1x1+m2x2...etc but I don't understand how you can do it...

Hi, I do not know how to get started for the following question, http://tinyurl.com/yueh5m can somebody help?

Homework Statement A uniform circular plate of radius 2R has a circular hole of radius R cut out of it. The center C' of the smaller circle is a distance 0.80R from the center C of the larger circle. What is the position of the center of mass of the plate? Homework Equations Hints...

Homework Statement Consider a system of two blocks that have masses m_1 and m_2. Assume that the blocks are point-like particles and are located along the x-axis at the coordinates x_1 and x_2. In this problem, the blocks can only move along the x axis. Find the x coordinate of the center of...

i am having some trouble understanding the concepts of center of mass for example using the equation (m1x1+m2x2)/(m1+m2) if m2>m1 what would be the center of mass i am not sure where to even begin

Question Details: I have two circles centered at the origin, one with radius A and the other with radius b. Looking at the hemiwasher (area between) the circles form above the x axis, find the values of A and B that place the center of mass within the hemiwasher itself, not in the open middle...

A bar is guided so that one end moves on a vertical line and the other on a horizontal line. A spring is attached to the upper end according to the figure. Any friction is neglected. http://web.comhem.se/~u48800174/springbar.jpg I want to find out how x varies in time. If the center of mass...

Homework Statement Three odd-shaped blocks of chocolate have the following masses and center-of-mass coordinates: (1) 0.310 kg, ( 0.200 m, 0.310 m); (2) 0.410 kg, ( 0.110 m, -0.380 m); (3) 0.200 kg, ( -0.280 m, 0.610 m). Find the x coordinate of the center of mass of the system of three...

Homework Statement A 2.80 kg particle has the xy coordinates (-2.00 m, 0.950 m), and a 3.30 kg particle has the xy coordinates (0.672 m, -0.0440 m). Both lie on a horizontal plane. At what (a)x and (b)y coordinates must you place a 3.39 kg particle such that the center of mass of the...

The ratio of the mass of the Earth to the mass of the moon is 84.5. Assume that the radius of the Earth is about 6578.0 km and that the distance between the center of the Earth and the moon is 385815.0 km. Determine the distance of the center of mass of the earth-moon system from the center of...

Center of Mass --True and False Homework Statement The center of mass of an object... 1.True or False exists only if the object is round. 2. True False exists only if the object is symmetric. 3. True False can be used to represent the location of the object's total...

Homework Statement (Q) Calculate the center of mass of a semi-circular metal plate of uniform density ρ and thickness t. Let the radius of the plate be a. The mass of the plate is thus 1/2 (ρπat2). In your co-ordinate system, you must consider the x-axis passing through the bottom of the...

3 equal masses lie at the corners of an equilateral triangle of side L. Where is the center of mass? ___ i know center of mass in the x-axis is just 0 which is apparent from symmetry, but how would you figure out center of mass in the y axis? i keep getting 0.577 L . someone please make this...

The Problem is the following: One half of a uniform circular disk of radisu 1 meter lies in the xy-plane with its diameter along the y-axis, its center at the origin, and x>0. The mass of the hallf-disk is 3 kg. Find(xcoord of center of mass, y-coord of center of mass) The equation of the...

Homework Statement Please help me calculate the center of mass of the polymer (radius) from atomic coordinates (more than 2000) given in Armstrongs. Can anyone help with the formula? I need to calculate the radius of gyration of the polymer. Thanks. Homework Equations The Attempt...

Homework Statement A space system consists of two visible stars, one is a blue giant with a mass of 11M and the other is a red dwarf with a mass of 0.5M. The system also has a black hole with a mass of 2M but we don't know where it is located. The blue giant is 700 gigameters away from you...

A space system consists of two visible stars, one is a blue giant with a mass of 11M and the other is a red dwarf with a mass of 0.5M. The system also has a black hole with a mass of 2M but we don't know where it is located. The blue giant is 700 gigameters away from you along the x-axis and...

[b]1. Recall that the blocks can only move along the x axis. The x components of their velocities at a certain moment are v1x and v2x. Find the x component of the velocity of the center of mass (vcm)x at that moment. Express your answer in terms of m1, m2, v1x, and v2x [b]2. Keep in mind...

A uniform sheet of metal is cut in the shape of a semicircle of radius R and lies in the xy plane with its center at the origin and diameter lying along the x axis. Find the position of the CM using polar coordinates. (Center of mass). [In this case the sum that defines the CM position becomes...

Homework Statement Consider a system consisting of two particles, one with three times the mass of the other. If the distance between the particles is 1.0 m, the system's center of mass is what distance from the smaller object? Homework Equations xcm = (m2/M)(D) = (m2 / (m1 + m2)) D...

I'm having difficulty in making two methods of the calculation of center of mass come out equivalently. One method is via intuition and the other is via standard formula. Homework Statement Find the center of mass of a semi-circular band of length L and mass M, and represent it in terms of...

Homework Statement Hey, I'm just doing a physics assignment and I seem to be having some issues. Its all written answers and no calculations are needed. We are meant to learn this topic by ourselves (over the holidays) and that's why I'm having some trouble understanding some of the concepts. I...

Homework Statement Two spheres of equal radius and masses 5.00 kg and 15.0 kg are sliding towards each other along the same straight line across a frictionless, horizontal surface. Vi1 = 15.0 m/s and Vi2= -9.00 m/s, respectively. During the collision, 25% of the total initial kinetic energy...

Homework Statement I know this sounds silly, but I need to understand where I'm going wrong here. Prove the center of mass of a spherical rigid-body (solid sphere) is found at the origin explicitly, using spherical coordinates (zenith, etc.). Homework Equations Centroid center of mass...

I'm having trouble finding the equation to find the center of mass between 2 masses. I'm guessing it's something like add the masses and find a ratio between them and apply it to the distance between their own center of masses but I'm not sure. can someone give me the equation and an explanation...

Homework Statement A block of mass m rests on a wedge of mass M and height H which, in turn, rests on a horizontal table. All the surfaces are frictionless. If the system starts at rest with the block on the top of the wedge, find the displacement of the wedge during the time the block...

fact - " the center of mass of an isolated system doesn't alter its position until an external force acts on it." ( I'm guessing its right) inexplicable(may be apparently) - " No body is pushing me. But I'm still moving" How do you explain that? Am i missing something?

Homework Statement A 3.0m long 10 kg plank has a 10 kg block mounted flush with the left end and a 20 kg block flush with the other end i.e. The outside edges of the blocks are 3.0m apart. A third block is set with its center of gravity right a the center of gravity of the system. If these...

how to show that the ratio of the distance between two particles from their centers of mass is the inverse of their masses? I tried but i found a way which can be possible if only we assume that they are constituted by a same number of small particles.

Finding the Center of Mass of a Person...Please Help me Out! Homework Statement In excersise physiology studies, it is sometimes important to determine the location of a persons mcenter of mass. ( It shows a picture of a girl laying on a plank with 2 scales under it) A light plank rest on...

Center of Mass, Momentum, and energy problem, shell seperation Homework Statement A projectile of mass 20.1 kg is fired at an angle of 65.0 degrees above the horizontal and with a speed of 79.0 m/s. At the highest point of its trajectory the projectile explodes into two fragments with...

Homework Statement A uniform rod of length 1.15m is attached to a frictionless pivot at one end. It is released from rest an angle theta=17.0 degrees above the horizontal. Find the magnitude of the initial acceleration of the rod's center of mass Homework Equations torque=moment of...

Homework Statement A 45.0-kg woman stands up in a 60.0-kg canoe of length 5.00 m. She walks from a point 1.00 m from one end to a point 1.00 m from the other end. If you ignore resistance to motion of the canoe in the water, how far does the canoe move during this process? Homework...

Homework Statement If you have a rod that is pivoted at one end with a mass of 4 kg and a length of 24 m and the other end has a sphere attached to it that is 4 kg and has a radius of 1.5 m, what is the center of mass?Homework Equations MXcm= m1x1 + m2x2The Attempt at a Solution I think that...

Here is the problem that I'm faced with: A 52 kg woman and a 80 kg man stand 12.0 m apart on frictionless ice. (a) How far from the man is their center of mass (CM)? (b) If they hold onto the two ends of a rope, and the man pulls on the rope so that he moves 2.8 m, then how far from...

Homework Statement Give the X, Y, and Z coordinates of the center of gravty of a half cubical block of uniform density. The diagram below shows how the block was cut. The diagram depicts a cube with sides of length 1 cut diagonally in half. the six vertices are as follows: (0,0,0) (1,0,0)...

[b]1. A composite slab has dimensions of d1=11.0cm, d2=2.80cm, and d3=13.0cm. Half the slab consists of aluminum (density=2.70g/cm^3) and half consists of iron (density=7.85g/cm^3). What are the x coordinate, y coordinate, and z coordinate of the slab's center of mass? There's a figure in...

General Question-- Compuing velocity of a center of mass Homework Statement A ball of mass 0.198 kg has a velocity of 1.47 i m/s; a ball of mass 0.309 kg has a velocity of -0.401 i m/s.They meet in a head-on elastic collision. (a) Find their velocities after the collision. (b)...

http://www.fileden.com/files/2006/11/15/381656/My%20Documents/problem%2013.jpg The figure above shows an arrangement with an air track, in which a cart is connected by a cord to a hanging block. The cart has mass m1 = 0.600 kg, and its center is initially at xy coordinates (-0.500 m, 0 m)...

A stone is dropped at t = 0. A second stone, with twice the mass of the first, is dropped from the same point at t = 250 ms. (a) How far below the release point is the center of mass of the two stones at t = 600 ms? (Neither stone has yet reached the ground.) (b) How fast is the center of...

Hi, sorry stuck again! Here is the problem: A projectile of mass 19.4 kg is fired at an angle of 57.0 degrees above the horizontal and with a speed of 81.0 m/s. At the highest point of its trajectory the projectile explodes into two fragments with equal mass, one of which falls vertically...

Hi there, I have a question about what I'm doing wrong with the following problem: A 45.0-kg woman stands up in a 60.0-kg canoe of length 5.00 m. She walks from a point 1.00 m from one end to a point 1.00 m from the other end. If you ignore resistance to motion of the canoe in the water...

Hi, I've been working on the following question for a little while. I've looked it over several times and I can't find any obvious (to me anyway) errors in my work. Would you please scan it through and let me know if I am correct or, if not, please guide me in the right direction so I can try...

this question has really stumped me. 23 people on a boat rest on water without friction. Each person has an average mass of 70 kg, and the boat itself weighs 10^4 kg. The entire party walks the entire 8 m distance of the boat from bow to stern. How far (in meters) does the boat move? i know i...

The Earth and moon are separated by a center-to-center distance of 3.85x10^8m. The mass of the Earth is 5.98x10^24kg and that of the moon is 7.35x10^22kg. How far does the center of mass lie from the center of the earth? I know you have to use the equation Xcm=m1x1+m2x2/m1+m2 I don't...

I really don't understand the concept of center of mass but i have a conceptual question that i am really not sure about. Where would you expect the center of mass of a doughnot to be located? Why? I mean gut instinct would tell me the center of the doughnut but there is no mass located...

If a particle of mass 5.30 kg is moving east at 10.0 m/s and a particle of mass 18.0 kg is moving west at 10.0 m/s, what is the velocity of the center of mass of the pair? I used the equation Vcm = P/M Vcm = [(5.70)(10) + (15)(10)] / [(5.70)+(15)] Vcm = 10 ms however, it says that...

A 50 kg person at the left end of a 75kg boat is 6 m from shore. The person walks to the other end of the boat 3m away. How far is the person from the shore now? The system center of mass fixed in space so as the person moves right, the boat moves left. I know that the person moves 3 m to...

After finding the center of mass of a pentagon with five equal sides a but one triangle missing, then iam asked to find the CM of uniform square a with one quadrant missing. I dont' really grab the idea of CM, please help..

Please check my answers. A 1200-kg station wagon is moving along a straight highway at 12.0 m/s. Another car, with mass 1800 kg and speed 20.0 m/s, has its center of mass 40.0 m ahead of the center of mass of the station wagon. a)Find the position of the center of mass of the system...