Recent content by mart7x

  1. M

    Real-world application of Active Stabilization Tanks in Ships

    Does anyone know any specific examples of real world application of Active Stabilization Tanks in a ship? I just need a link to an article or just a name of ship IF one exists. I have been doing some research into A.S.T's and I am desperate to find out if the concept has been manufactured. I...
  2. M

    Force required to start rolling a wheel ?

    rayallenvn I think I have found a suitable answer on a separate thread (https://www.physicsforums.com/showthread.php?p=3861678#post3861678). Basically what I got confused at is modelling the sphere either in an real or ideal world: In an ideal world (the surface and wheel are both rigid), the...
  3. M

    Static Friction, Kinetic Friction and Rolling Resistance query.

    AHH well it is a slightly unique (maybe controversial!) theory that I have been hired not only to validate but to critique- To put it as simply as possible: hundreds of carved granite spheres have been found around monuments such as stonehenge with deviations in diameter of less than 2mm (I...
  4. M

    Static Friction, Kinetic Friction and Rolling Resistance query.

    Thank you very much I have been struggling for a long time to set this record straight! To put this into context, I am creating an experiment within the lab which is testing the horizontal force to move large monument stones (such as Stonehenge in Britain) when resting on rollers/carved ball...
  5. M

    Static Friction, Kinetic Friction and Rolling Resistance query.

    Sorry forgive me if I'm repeating what has been mentioned, but to clarify rolling resistance IS applicable to a stationary object (that could potentially roll)? I have a stationary sphere of mass = 10kg, Coefficient of Rolling Resistance = 0.05. The force required to start the ball rolling...
  6. M

    Static Friction, Kinetic Friction and Rolling Resistance query.

    Ok brilliant, but I don't use the rolling mass for a stationary object (not yet rolling), right? And could I possibly find the force to move the sphere if I didn't know the acceleration- essentially the critical force that I would need to apply to initiate rolling? Thanks for all the help!
  7. M

    Force required to start rolling a wheel ?

    Thanks Bob. To clarify- even when a wheel is stationary, the minimum force required to initiate motion if RRC * Normal Force?
  8. M

    Force required to start rolling a wheel ?

    rayallenvn I am also having a lot of difficulty finding a definitive answer for this question... Similarly to an example of the force required to move a stationary block (a fairly simple problem) I am looking to work out the force required to move a stationary wheel. However in my case there...
  9. M

    Static Friction, Kinetic Friction and Rolling Resistance query.

    Ok thanks tiny-tim, is it then just mass of the sphere that is resisting motion? I have a slab resting on a few spheres and I am experimentally testing the force required to move it, but I would like to first model the problem analytically. How then do I go about finding the force required to...
  10. M

    Static Friction, Kinetic Friction and Rolling Resistance query.

    Hypothetically, if I had a sphere and a block (of the same mass and material (hence the same coefficients of static friction for both interfaces) both stationary on a surface, they would require the same force to initiate motion? Once moving, a coefficient of sliding friction is employed in...
  11. M

    Coefficient of 'Kinetic' Rolling Friction(?)

    So... for a wheel for example: Stationary - Coefficient of Static Friction, Rolling - Coefficient of Rolling Friction. If a surface was made of wood, a wooden wheel would have the same resistive force as a block of wood when resting stationary on top (assuming they have the same mass)?
  12. M

    Coefficient of 'Kinetic' Rolling Friction(?)

    When looking at rolling objects, the force of rolling resistance is determined by a coefficient of rolling friction. Is this coefficient constant for an object when both stationary and moving? Or is there a separate static and kinetic coefficient as there is with sliding friction? I am asking...
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