What is Mass distribution: Definition and 36 Discussions

In physics and mechanics, mass distribution is the spatial distribution of mass within a solid body. In principle, it is relevant also for gases or liquids, but on earth their mass distribution is almost homogeneous.

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  1. I

    Dimensionless value to differentiate between concentrated and dispersed

    I want to find a dimensionless value that differentiates between concentrated mass systems such as the solar system and dispersed mass systems such as a galaxy. I assume spherical and radial symmetry, consider both the cases for point masses or smooth mass distributions. The only value I can...
  2. cosmologyscience

    I Orbital Velocities and Mass Distribution in Galaxies

    Has anyone looked into the details of stellar orbital speeds and required (visible) mass distribution in the Milky Way? Doing some math here - if the local mass density is significantly higher in the inner 10-15% of the galaxy, and then lower and gradually thinning outwards in the disk, we will...
  3. Ranku

    I Mass distribution in a celestial system

    If two sets of objects, of similar size but different mass, were to be part of a rotating celestial system, how differently would they be distributed? Would the distribution of the lower-mass objects be more spread out, while the higher-mass objects would be concentrated toward the centre?
  4. Barbequeman

    Consider three models of the Mass distribution in the Milky Way

    I attached a Jpeg with my attempted solution but I´m not sure if I´m on the right way... I hope for a correction in my calculations
  5. DarkMattrHole

    I Mass distribution behavior of the singularities during black hole mergers

    When two BHs collide the resulting single BH bulges and contorts until it settles down to a stable state. 1) Does this mean that during this 'settling' period the mass internal to the merged BH is not (yet) a singularity, but instead two 'singularities' spinning down around each other in...
  6. S

    Relation between mass distribution and angular velocity

    Is E the correct answer because I think angular velocity is independent of mass distribution of the object? Thanks
  7. R

    Volume of smaller pyramid is less than the volume of the whole.

    I have a test coming up next week and while doing some practice questions I found one I can't wrap my head around. The question is: A pyramid (assume uniform density) is divided in two parts by a horizontal plane through its center of mass. How do the masses of the two parts compare ? There are...
  8. L


    Let's say 5 masses are arranged on x axis. At x=1, 2kg X=2, 4kg X=3, 6kg X=4, 8kg X=5, 10 kg Obviously, there is a total mass of 30 kgIf the mass is distributed continuously by the function M(x) = 2x, then From x= 0 to x=5, there is 25 kg of mass from the simple integral. WHY IS THERE LESS...
  9. M

    A Does continuous mass distribution implies finite propagation

    speed? This question emerged in my mind while studying a discrete and continuous mathematical model of a falling slinky. In the discrete model, we suppose an instantaneous interaction between mass points at a distance, so the action propagates through the chain of mass points with infinite...
  10. J

    A Galaxy mass distribution without DM

    I've searched for a formula of galaxy mass Distribution formula along the radius, often the papers say: ρ∝ex ( ρ is the surface density, x is distance from the Center of the galaxy). is it correct without DM? Or is there any other correct formula?
  11. D

    B Simple cheap method of measuring mass distribution of object

    I'm looking to measure the weight of an tennis racket at different lengths. Obviously If I stick it on the scale it will give roughly the sam,e weight no matter if I put the whole racket on, or a third of the racket. Would there be a way I could measure the weight, of say the first third of an...
  12. Z

    How Does Mass Distribution Affect Rotational Inertia?

    This isn't actually a homework problem, but I am still posting it here. I am confused by rotational inertia. How does mass distribution affect rotational inertia? Because I know it should, but I don't know how it would.
  13. Essence

    Ideal Rocket Mass Distribution

    Note: I have noted that one of the formulas I have provided does not show up on my webpage in preview mode and so have also made it as an attachment. Quick summary: I have found two different websites that offer the equation that I am looking for in different forms, but I am starting to think...
  14. J

    Mass distribution of a semi-infinite stick

    Homework Statement Given a semi-infinite stick (that is, one that goes off to infinity in one direction), determine how its density should depend on position so that it has the following property: If the stick is cut at an arbitrary location, the remaining semi-infinite piece will balance on a...
  15. Omega0

    Exploring Universe Mass Distribution - A Database Guide

    Hi, Where can I find a database with the mass distribution and its movement in the well-known universe? Best wishes, Jens
  16. AlanKirby

    What is a Decay width really, qualitatively?

    Hi there, my question is along the lines of the following. I understand that in an experiment we obtain a distribution of masses for a given particle, due to the finite resolution of the detectors. In terms of a fundamental (if that even makes sense) decay width, what is the decay width? Is it...
  17. E

    Computing Mass Distribution in Statics Problems

    Hello, I would like to ask the following question : --> I have an object of mass M (represented by the blue potato in the two attached drawings). --> I know the coordinates (x,y) of its Center of Gravity (reprensented by big red cross). --> I also know the coordinates of its contact points to...
  18. carllacan

    What is the distribution of mass in an atomic nucleus?

    Hi. This may be a trivial question, but I'm unable to find a definitve answer. How is the mass on a atomic nucleus distributed? I read somewhere that it was uniformly distributed, and somewhere else that it resembled a normal distribution. Can you help me out? Thank you.
  19. omarMihilmy

    Understanding Center of Mass Distribution in Rotational Equilibrium

    Isn't the point of center of mass is where the masses on both sides are equally distributed? Why is it not the case here?
  20. N

    Total mass from mass distribution function

    Homework Statement An obect whose mass is distributed according to function m(r)=m0e-r, for r ranging from 0 to ∞. Calculate total mass of the object. Write down and evaluate appropriate integral. 2. The attempt at a solution well, I wasnt sure really how to start but thought it may be...
  21. D

    Why Do Nuclear Mass and Charge Distributions Follow the Same Function?

    why do we say that nuclear mass distribution and nuclear charge distribution follows the same function while nucleus has both charged and uncharged particles?
  22. M

    Exploring Mass Distribution in LCDM Cosmological Model

    Hi, I am trying to get a better understanding of the mass distribution as described by the LCDM cosmological model and data that might be more anchored in observation. What I mean by this is that the LCDM model appears to operate on the assumption of the large-scale homogeneity of the universe...
  23. A

    The effect of mass distribution on acceleration of a car.

    Hi, I am amidst writing my 4k word high school physics paper (IB extended essay) and am in need of some help/guidance. The experiment I am conducting is as stated above. I have been changing the distribution of a set of masses from front, middle and rear on a model car and recording changes in...
  24. F

    Mass distribution and gravitational field

    The field outside a body with spherical mass distribution is well known but for a non simmetrical body (or a almost simmetrical body like the earth) which is the approach?. Do you know any reference? thank you
  25. P

    Mass distribution inside the event horizon

    In the popular physics books that I enjoy reading, black holes are described as containing a singularity of zero volume that contains 100% of the mass. I can't envision this, since 100% of the spacetime inside the event horizon would then be empty space except for virtual particles. Is this...
  26. C

    Mass distribution of a black hole?

    Why can't we know the mass distribution inside a black hole. If we are observing from outside the event horizon I couldn't tell how the mass was moving around inside the black hole, I could just figure out how much was in there by measuring the G field.
  27. H

    Optimal mass distribution for maximal gravitational field

    Homework Statement Suppose that one is given a lump of clay of total mass M and constant density. Let P denote a particular point in space. In what way should one shape and position the clay so that the gravitational field in point P is maximum possible? It is assumed that the clay stays in...
  28. J

    Mass Distribution: Polar Icecaps Melting & Day Length

    Homework Statement If the polar icecaps melted, the resulting water would spread over the entire earth. This new mass distrubtion would tend to make the length of a day: a.longer,b.shorter,c.be unchanged,d.explode Homework Equations Mass does distribute uniformly but I am not sure how...
  29. D

    Mass Distribution between Car Tires

    Hi all, I'm writing a car simulation for a game engine, and this problem has me going bonkers. For a car with known mass and center of mass, how can you figure out the "share" of mass that each tire is supporting? For standard tire arrangements (4 tires on 2 axles) I know it's just a ratio...
  30. M

    Determining mass distribution for team-lifting of arbitrary objects

    Hey all, New to the forum (obviously, since this is my first post). I've been scouring the internet trying to find some guidance on a problem I've been having, but have had no luck. Let me just say first off that my physics and math backgrounds are fairly elementary. I have minors in both...
  31. J

    External gravity field independent of mass distribution?

    Hi. Gauss' law applied to gravity states that the gravitational flux through a given surface is proportional to the total enclosed mass. Considering a gaussian surface which encloses a continuous mass distribution, an arbitrary re-distribution of the total mass must yield the same value...
  32. M

    Symmetry of mass distribution producing radial gravitational force field

    I conjecture that only spherical symmetric mass distribution can produce radial gravitational force field (according Newton's law of gravitation). Can anybody prove or disprove this conjecture?
  33. G

    Question: Mass distribution in galaxies

    What is a typical distribution of mass in a typical spiral galaxy. I understand most is in the centre, but how much? How much in the outer regions? Can anyone point me to graphs or tables? Much appreciated.
  34. P

    Proving $\tau = I\alpha$ for Continous Mass Distribution

    how does one prove \tau=I\alpha for continious mass distribution where \tau is the net external torque along the axis of rotation I is the moment of inertia,and \alpha is the angular accelaration ... i know the proof when the mass distribution is discrete...
  35. B

    Deriving Mass Distribution & Rotation Curve Function

    Hello everyone... can someone help me with this problem please: The rotation curve V(r) for a mass distribution characterizes the rotational velocity of a test particle in orbit in its gravitational field as a function of radius from its center. Suppose you have a spherically symmetric mass...
  36. I

    Solve the Puzzle: Find the Scale Readings for a Mass Distribution

    formula Help! i got this question but i don;t know which formula to use Q - A 1m plank of Mass 1.0kg is placed on two scales which are at either end of the plank. Masses are hung underneath the plank. Mass A = 5.0kg at a distance of 0.30m from the left of the plank Mass B = 5.0kg at a...