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Homework Help: Concept: Air Resistance in Projectile Motion

  1. Feb 18, 2012 #1
    Hi, I am in need for some physics help regarding the effect of air resistance on projectile motion.

    My question is "For a tennis ball stuck at an angle of 45 degrees to the horizontal at typical speed without spin, why does air resistance have a greater effect on the horizontal range of the ball rather than the maximum height of the ball?"

    I've tried searching Google for a solution, but have yet been able to find one. I don't just want to copy the answer off of the internet, but actually learn the concept.

    Any help is much appreciated,

    In my notes I have:

    For launch angle of 45 degrees, Vh and Vv = sin45 and cos45 = 0.707N (I have no idea why it says Newtons here if it's talking about velocity)

    And then my notes say: "Theory: Vh= constant = x. Vv= x --> 0 --> x. Average Vh = x (more friction), Average Vv=x/2 (less friction)"

    I am still unsure as to what all of this means. What is the reasoning behind the horizontal range being affected more by air resistance than the vertical height? Does it have something to do with friction forces being larger when velocity is larger?
    Last edited: Feb 18, 2012
  2. jcsd
  3. Feb 18, 2012 #2


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    Here is a hint: in which case do you feel more wind? Driving at 10mph? Or driving at 60mph?
  4. Feb 18, 2012 #3
    You'd feel more wind driving at 60mph, yeah? I know that there's more friction the faster you are travelling, but I am unsure as to how this affects horizontal distance more than vertical distance. What is the concept behind this?
  5. Feb 18, 2012 #4


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    What is the average velocity of the ball in the y direction as compared the average velocity of the ball in the x direction? They definitely be can't the same since at one point in its trajectory, y velocity is zero.
    Last edited: Feb 19, 2012
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