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Homework Help: Calculate the maximum force required to accelerate the box

  1. Jan 12, 2012 #1
    1. The problem statement, all variables and given/known data
    Calculate the maximum force required to accelerate the box from rest and not move the glass on it's surface on top of the box. I am given the mass of the box and glass, and both the static and kinetic coefficients of both objects. I have to create a spreadsheet that can accept any number that is inputted

    2. Relevant equations
    Ff=umg, fnet=Fg+Fn+Ff+Fa

    3. The attempt at a solution

    so far ive got the maximum force of static friction for the glass, using the equation F=umg... Im unsure how the box beneath it affects the force applied to the glass
    Last edited: Jan 12, 2012
  2. jcsd
  3. Jan 12, 2012 #2
    Re: Friction

    The maximum force will give you the maximum acceleration, a. The required force must accelerate both masses with acceleration a and oppose the friction force on the box (don't forget the mass of the glass increases the friction force).

    Hope this helps.
  4. Jan 12, 2012 #3


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    Staff Emeritus
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    Re: Friction

    Hello charch. Welcome to PF !

    Draw two free body diagrams; one for the box, one for the glass.
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