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Homework Help: A tennis ball is flying horizontally across the net. Air resistance is not negligible

  1. Oct 23, 2008 #1
    Identify the forces on the ball.

    Static Friction
    Normal Force
    Kinetic Friction

    I'm sure that there is weight and normal force and that there is not tension. I'm also fairly sure that there is no static friction but I am not sure about drag and kinetic friction. I know that this is a pretty easy question but I can not seem to get the hang of it.
  2. jcsd
  3. Oct 24, 2008 #2
    Re: A tennis ball is flying horizontally across the net. Air resistance is not neglig

    I think you need a better understanding of the terms. Static friction is when two solid objects try to slide across each other but do not move.

    Weight is the earth pulling down on stuff.

    Normal force is when two solid objects are in contact with each other. It stops objects from going through each other and it's why I can't walk through walls except through a doorway.

    Kinetic friction is when two solid objects slide across each other. One (or both) of the objects moves.

    Tension is when something is being pulled by a rope, a thread, or for that matter any solid object that touches another object but pulls rather than pushes. Tension is between two solid objects (a rope, for example, is a solid).

    Drag is when an object pushes against a liquid or a gas.

    So, if the tennis ball, which is a solid, is only touching the air, which is a gas, then is there a normal force between the two?
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