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Air resistance and acceleration

Discussion in 'MCAT Study Question Q&A' started by m25, Sep 5, 2014.

  1. m25

    m25

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    If we are taking air resistance into account, when two objects of different masses are dropped, is the lighter object experiencing less acceleration in the downward direction?
     
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  3. Cawolf

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    If we look at two objects that are identical except for mass we can compare.

    Lets say the more massive object has mass M, and the lighter object is mass m = 0.5M.

    Just looking at vertical forces. We can also state that the drag forces will be identical, since it is not based on mass, so drag force = D.

    Massive
    F = MA = Fd + Fg = D - Mg

    Ma = D - Mg

    A = (D - Mg)/M = (D/M) - g

    From that calculation we know the acceleration of the lighter object is a = (D/m) - g

    a = (D/m) - g = (D/0.5M) - g = (2D/M) - g

    So more massive object A = (D/M) - g < a = (2D/M) - g

    Therefore we know the lighter object is feeling a more positive upwards force (or less force downwards).

    Since the lighter object has less downwards force, it experiences less downwards acceleration.
     
    #2 Cawolf, Sep 5, 2014
    Last edited: Sep 5, 2014
    DrDreams likes this.
  4. m25

    m25

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    Ah, perfect. Thank you!
     
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