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NTNUJAVA Virtual Physics Laboratory (Java Simulaions in Physics) > JDK1.0.2 simulations (1996-2001) > Dynamics > Frictional force
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Author Topic: Frictional force  (Read 88491 times)
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Fu-Kwun Hwang
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« on: January 29, 2004, 03:47:22 PM »
Registed user can get files related to this applet for offline access.
If java program did not show up, please download and install latest Java RUN TIME
There are 3 translations,
or




A mass m1 rest on top of another mass , m2, which is connected to m3 by a light rope</p>
    (passes over a frictionless pulley).

This java applet show the force diagram and the motion of the system when the frictional forces are present.

    The mass of each block is shown at the lower-right corner.
    Assume the coefficients of friction between any two surfaces are the same.
    Force diagram for mass m2 is shown to the left .



      Color of arrowblackbluegreencyanredyellow
      forcegravitynormaltensionfrictionfrictionNet force on m2
      sourceearthtableropem1table

    Click within the white area of each block to change its mass.
      Click right mouse button to increase one mass unit, click left mouse button to decrease one mass unit.


    Press Start will start the animation, click mouse button to suspend the animation, click it again to resume.
    Press Reset for default parameters.


  • Play it! and find out under what kind of condition:

    1. m1 and m2 would not be accelerated? (Net force =0.)

    2. m1 and m2 are accelerated together.

    3. m1 and m2 are accelerated differently. (a1 a2 which one is larger?)



    This is a sample gif picture.


      The mass of the blocks are m1, m2,m3 , accelerations are a1, a2 , a3 .
      The normal force between m1 and m2 : N12= m1 g, (where g is the gravity field strength)
        so the frictional force f12 m1 gu .

      The normal force between m2 and the table : N2= (m1+m2) g
        so the frictional force f2 (m1+m2)gu

      The tension of the rope is T.
      For m1 : f12 = m1 a1
      For m2:If T &gt; ( f12+ f2 ) then T - ( f12+ f2 ) = m2 a2
        otherwise f2 = T and a2= 0.

      For m2: T - m3 g = m3a3


    From the above equations, we can find out the accelerations.

    I did that calculation already! It is your turn to do it now! O.K.


    Registed user can get files related to this applet for offline access.
    If java program did not show up, please download and install latest Java RUN TIME
    There are 3 translations,
    or
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    « Reply #1 on: January 30, 2004, 08:03:35 AM »
    Subject: Your Java Frictionnal Force applet.
    Date: Mon, 9 Feb 1998 11:45:31 +0100
    From: "leflocht" <leflocht@wanadoo.fr>
    To: <hwang@phy03.phy.ntnu.edu.tw>
    Thanks a lot for your on-line physics lesson.
    As a french teacher i would like to ask you the permission to use your applet on a new html sheet
    using french as basic language. Of course i would only translate your words( the best i can)
    and leave each reference (native URL, mailto.. and comments in original state.)
    The reason is that i just gave my students, (aged 17) a exam using the study of this system.
    So i would like them to use your applet to get more of this study case by using new parameters
    such as Mu and various masses.
    This page, if possible, will be added to the site i create for my sudents (it's the very beginning),
    you could surf at: http://www.chez.com/bup/index.htm and find it using french "Fichiers de TP" in the 1S section.
    ---- You ask for suggestions ? Of course i've got some.
    *first: The masses you use : Are F1 = 10 grams or F1 = 10*g where 10 is kg and g is 9.81 mS-2 ?
    (and so on for others )? case 10 grams: we use to calculate Force intensity in Newton (France) case 10 kg:
    the mass seems very heavy !
    *second: Some lines of your HTML page are not readable for french users because of the asian keyboard
    translation,( i think.) Just above the definition table of forces, there is a line i'dont know what it is ?
    (caracters like @#& and others not in use in our alphabet but for bad words ...)
    The definition for f12 is quite the same it appears like: f12j[number zero]m1 g[symbol for english pound] g
    I think we must read: f12 not so different of m1. Mu.g. ad so on for each reading of friction force. -----
    I can make, if you look for it, other text translations, so your work to make your work used by french people.
    Thanks .
    Thierry Le Floch Thanks to disregard my english mistakes.
    -------------------------------------------------------------------
    Thierry Le Floch
    Email: leflocht@wanadoo.fr site
    http://perso.wanadoo.fr/thierry.lefloch/
    UIN 4557973
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