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Homework Help: Falling under Gravity

  1. Dec 8, 2015 #1
    1. What have I done wrong when I set this GCSE question?! (shortened)
    Gravity: 10 N/kg
    Bowling ball: weight 10 N, air resistance 0.05 N, overall force 9.95 N
    Football: mass 0.5 kg, air resistance 0.05 N

    Students need to work out:
    • effective force on the football (4.95 N)
    • bowling ball (a = F/m = 9.95 / 1 = 9.95 N/kg)
    • football (a = F/m = 4.95 / 0.5 = 9.9 N/kg)
    So... what have I messed up as I'm pretty sure their acceleration should be equal!?

    2. Relevant equations
    F = ma, W = mg

    3. The attempt at a solution
    I have played around with it and I'm missing something, help!
  2. jcsd
  3. Dec 8, 2015 #2


    User Avatar

    Staff: Mentor

    Why should the acceleration be the same when you take into account air resistance?
  4. Dec 8, 2015 #3
    Dumb... thanks for pointing out the obvious!
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