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Homework Help: Questions in [ motion in two dimensions ]

  1. Oct 21, 2009 #1
    questions in [ motion in two dimensions ]

    q. [ .. if you know the position vectors of a particle at two points along its path and also know the time interval during which it moved from one point to the other m can you determine the particle's instananeous velocity ? its average velocity ? Explain.

    q. [.. a projectile is launched at some angle to the horizontal with some initial speed vi and air resistance is negligible . is the projectile a freely falling body ? what is its acceleration in the vertical direction ? what is its acceleration in the horizontal direction ?

    q. [ ..O stat which of the following quantities , if any , remain constant as a projectile moves through its parabolic trajectory :(a) speed (b) acceleration (c) horizontal compnent of velocity (d) vertical component of velocity .
  2. jcsd
  3. Oct 21, 2009 #2
    Think about it a little.

    1) Instantaneous velocity is it's velocity at any given point right at that instant. Average is it's velocity over some distance for some amount of time.

    2) If you throw a ball, after you throw it, what forces are acting on it? And what direction do those forces pull? there is no acceleration without a force.

    3) You need to look at each of those quantities and think about what happens to a ball when thrown. Remember, after the ball leaves your hand, only certain forces are working on it. Acceleration will only change due to a force. Velocity will only change due to an acceleration.
  4. Oct 21, 2009 #3
    Thank u alot ,,
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