Center of mass Definition and 899 Threads

Chapter 7, Problem 56 The drawing shows a sulfur dioxide molecule. It consists of two oxygen atoms and a sulfur atom. A sulfur atom is twice as massive as an oxygen atom. Using this information and the data procvided in the drawing, find the y coordinate of the center of mass of the...

The drawing shows a human figure approximately in a sitting position. For the purposes of this problem, there are three parts to the figure, and the center of mass of each one is shown in the drawing. These parts are: (1) the torso, neck, and head (total mass = 41.5 kg) with a center of mass...

I'm having a hard time with these center of mass problems. The lecture that my professor gave on this wasn't very descriptive. Could someone show me the whole process of finding the center of mass? A uniform plate of height 0.720 m is cut in the form of a parabolic section...

If a particle of mass 5.3 kg is moving east at 10 m/s and a particle of mass 19 kg is moving west at 10 m/s, what is the velocity of the center of mass of the pair? This one should be simple, here is my work: Vcm = (m1v1 + m2v2) / (m1 + m2) (-5.3kg*10m/s + 19kg * 10m/s) / -5.3 + 19 =...

I am having a tough time with this one... Body A of mass 4 kg is moving in the +x-direction with a speed of 15 m/s. Body B of mass 5 kg is moving in the -y-direction with a speed of 8 m/s. What are the x- and y-components of the velocity of the center of mass of the two bodies? How do I relate...

For some reason I can't seem to figure this question out. I get the feeling it's much easier than I'm making it. But here it is: Ball 1, ball 2, and ball 3 have masses 1 kg, 2 kg, and 3 kg respectively, and are initially arranged at x = 1 m, x = 2 m, and x = 3 m respectively. y = 1 m for...

Dave Johnson, the bronze medallist at the 1992 Olympic decathalon in Barcelona, leaves the ground at the high jump with vertical velocity component 6 m/s. How far does his center of mass move up as he makes the jump? I've got nothing for info how do I solve this?

Lets say I have some convex shape defined by a set of points in a clockwise direction. How do I calculate the MOI and the COM?

Can someone explain how center of mass changes? We haven't actually learned about the center of mass, so I don't know how to even approach this homework question. ok so here's the question: If you stand with your back against a wall, you find you can not bend over to pick something up...

On earth, under the influence of gravity, when an object is spun/rotated and then released, it will find its center of mass and rotate around that as it falls. So, if you spun a very straight uniform stick at its exact center of mass say 1 meter off the ground and then released it, it will drop...

A big olive (m = 0.11 kg) lies at the origin of an xy coordinate system, and a big Brazil nut (M = 0.82 kg) lies at the point (0.99, 2.1) m. At t = 0, a force Fo = (4i + 4j) N begins to act on the olive, and a force Fn = (-4i -3j) N begins to act on the nut. What is the (a)x and (b)y...

A big olive (m = 0.11 kg) lies at the origin of an xy coordinate system, and a big Brazil nut (M = 0.82 kg) lies at the point (0.99, 2.1) m. At t = 0, a force Fo = (4i + 4j) N begins to act on the olive, and a force Fn = (-4i -3j) N begins to act on the nut. What is the (a)x and (b)y...

1) A force F = A/t^2 acts on an object. At time t = t_o its momentum is 0. What is its momentum after a very long time? First I used Newton's second law: dP/dt = A/t^2 Then t^2 dP = A dt dP = A/t^2 dt And I took the integral of both sides, the left from 0 to P, the right from t_o to t...

centroid ("center of mass") of cardioid I'm having trouble calculating the centroid of the cardioid (and various other polar-coordinate-defined lamina), i.e., r = 1 +\cos \theta I can see how it's symmetric over the x-axis, so y-bar is zero. So to calculate x-bar, then I do...

A 1470 kg automobile has a wheel base (the distance between the axles) of 2.70 m. The center of mass of the automobile is on the center line at a point 1.20 m behind the front axle. Find the force exerted by the ground on each wheel. A bit confused here. Were going to use the sum of the...

:cry: been wonderin' for an hour already nac somebody please answer if there is a difference between the center of gravity and the center of mass if there is, what is it?

Finding the center of mass of a two dimensional object of constant density is a question that frequently occurs on my Mu Alpha Theta tests. I know of a long way to find it which I'll show in a moment using single integrals. I'm wondering if using double integrals can shorten this considerably...

Does the center of mass between the Earth and the moon follow an elliptical path around the sun? Does it wobble a little bit?

We have a block of un-uniform density of mass m suspended by two massless wires, against gravity. The left wire makes an angle phi_1while the right angle makes an angle phi_2. The block has length L. They want me to find the center of mass. THis is what I've done: We have tension in the wires...

hi,Center of mass is supposed to be this one particular point that behaves as if the whole body mass was located there. Since human body is not rigid does its center of mass change when for example person raises his/her arms or leans forward? thank you

hi, I am finding the center of mass in this problem. I have it as an attachment. Please take a look, thanks.

Hey, There is a question in my textbook that I don't understand the answer too. THey show a diagram of a baseball bat and say if the baseball bad it cut at the location of its center of mass, do the two pieces have the same mass? They say no, the piece with the handle will have less mass than...

To determine the location of his center of mass, a physics student lies on a lightweight plank supported by two scales L = 3.90 m apart. http://forums.cramster.com/answer-board/image/b34f433113a2369128cc61ed29304ffd.jpg If the left scale reads 250 N, and the right scale reads 106 N, find the...

hey everyone, I am stumped as to finding the x and y coords of the center of mass of this picture. it is supposed to be a uniform sheet of steel in increments of 6. please help, i have an exam tomorrow.

Hello A cable is attached at two (nonemoving)fixpoints. Now the cables midpoint is pulled downward, thereby destroying the catenary curve. Question: How will the cables center of mass (CM) move: op, down or stay fixed? My thoughts: I find it intuituitive that the CM will assume the...

I am trying to understand this example of finding the center of mass of a uniform solid cone. please refer to the attached figure. We know for obvious reasons that the center of mass will be on the z-axis. I will be referring to the integral that my book used to find the center of mass which is...

I don't understand how to approach this question, I'm lost in where energy gets involved. Any help would be appreciated :smile: A 110kg person is traveling at 3 m/s on a frictionless surface toward a wall, then stops themselves by pushing against the wall. During the push, the person's...

ok here is the problem <br>A uniform meter stick of mass M has a half-filled can of fruit juice of mass m attached to one end. The meter stick and the can balance at a point 33.0 cm from the end of the stick where the can is attached. When the balanced stick-can system is suspended from a...

I am having difficulty solving the first part of this problem. I have tried to many ways to find the ratio of m_a/m_b but I can't seem to get the correct answer. Can someone point me in the right direction. Thanks.

The ratio of the mass of the Earth to the mass of the moon is 77.6. Assume that the radius of the Earth is about 6404.0 km and that the distance between the center of the Earth and the moon is 380604.0 km. Determine the distance of the center of mass of the earth-moon system from the center of...

I'm sitting in my car on a flat road while it is stationary. The only forces acting on my car for this exercise are gravity and the normal force, which add up to give no net external force on my vehicle and me. My center of mass is at a fixed point somewhere in the vehicle, and according to the...

1. The ratio of the mass of the Earth to the mass of the moon is 77.6. Assume that the radius of the Earth is about 6404.0 km and that the distance between the center of the Earth and the moon is 380604.0 km. Determine the distance of the center of mass of the earth-moon system from the center...

Hi, Ok so we were told to find our center of mass using the reaction board method, but modified. We just do a pushup position with our hands on a scale, I have a electronic one and toes on the floor. My values obitained are: weight=68kg the scale reading in a pushup position=48.9kg...

A dog, with a mass of 12.0 kg, is standing on a flatboat so that he is 25.5 m from the shore. He walks 6.0 m on the boat toward the shore and then stops. The boat has a mass of 46.0 kg. Assuming there is no friction between the boat and the water, how far is the dog from the shore now? i used...

A 44 kg woman leaps vertically from a crouching position in which her center of mass is 48 cm above the ground. As her feet leave the floor her center of mass is 81 cm above the ground; it raises to 124 cm at the top of her leap. What average force was exerted on her by the ground during the...

I came across a particular result which bothered me, it stated that: Result: A person bending to 90 degrees at the waist with their back to a cliff will fall because their center of mass is past their feet. This statement perturbed me, because, when I applied it myself, I found that, while I...

A thin rectangular plate of uniform area density = 2.86 kg/m^2 has a length of 42.0 cm and a width of 23.0 cm. The lower left hand corner is located at the origin, (x,y)=(0,0) and the length is along the x-axis. There is a circular hole of radius 7.00 cm with center at (x,y)= (15.00, 9.50) cm...

Two blocks each of length L are piled near the end of the table. What is the maximum distance between the edge of the table and the edge of the outer block before the system topples? I understand that if the center of mass of the system must be to the left of the edge of the table for the...

I need to find the center of mass of a cone with point facing downwards, of height H and radius R. Since the density is constant throughout and because of axial symmetry the center must be somewhere on the z-axis. I know from convention that this is H/4 but i need to derive this. Rcm...

The triangle has uniform surface mass density of. The method that I've been taught involves some basic integration and substitution of dm for (Density X dA). And then substituting dA with one expression in terms of dy, and another in terms of dx. I don't really like the method I was...

An object rolls because of friction yea? So does that mean a torque is produced when the ball is given an initial push? I mean there is a force, and the force is perpendicular to the line which connects to the center of rotation, so this would be logical yea? But if there is a torque, then...

Why when we throw an extended object like a baseball bat will the center of mass follow the same parabolic path that we expect for a smaller obeject like ball, while the bat itself will rotate around this ceneter of mass? Why does center of mass behave like a simpler object? thank you

1. How is it that when high jumpers go over bars, their centers of mass pass underneath? 2. why must a hockey stick that is thrown rotating on ice stop rotating at exactly the same time as when the center of mass comes to rest?

it is said that the posiion vector of the cener of mass of a rigid body can be obtained by: r_{CM}= \frac{1}{M} \int r dm I'm not sure I understand this expression. What exactly is dm? and I thought it was the sumation of mass times distance divided by the total mass...

Hi, I was hoping to gather some feedback for one of my homework problems. Any help would be much appreciated. The problem is as follows: A mortar fires a shell of mass m at speed v_0. The shell explodes at the top of its trajectory as designed. However, rather than creating a shower of...

A 2.81 kg hollow cylinder with inner radius 0.29 m and outer radius 0.5 m rolls without slipping when it is pulled by a horizontal string with a force of 47.7 N, as shown in the diagram below. Its moment of inertia about the center of mass is .5m(r(out)^2 + r(in)^2). What is the...

A solid shere of mass M and radius R rolls without slipping down an inclined plane whose incline angle with the horizontal is 30 degrees. What is the acceleration of the sphere's center of mass? gsinX is the acceleration, so it would be g/2 right?

I am having the hardest time figuring out the center of mass of this problem. A sheet of metal is cut in the shape of a parabola (imagine that you have a parabola shape with the top being flat). The curved edge of the sheet is specified by the equation y=ax^2, and y ranges from 0 to b. Find...

I have been missing for class 3days and i was get lost because my daughter gets sick in the past weeks :cry: :( until todate. The problems i need everyone helps below are just a sample exam. I have contact my professor about my family problems and he was nice, gave me the sample exam which it's...

Greetz :) I recently found this problem and have made a few attempts at answering it but still have not found an answer i am 100% confident with, I would appreciate it if anyone who is keen to attempt it could give some advice and explanations for their reasoning in the solving of this...