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Homework Help: Writing Equations for Position, Velocity, and Accelerations as functions of time

  1. Jan 22, 2009 #1
    1. The problem statement, all variables and given/known data

    A projectile is launched with a speed of 50.0 m/s and an angle of 40.0o above the horizontal, from the top of a 75.0 m high cliff onto a flat valley floor at the base of the cliff. Assume that g = 10.0 m/s2 and ignore aerodynamic effects.

    Write equations for position, velocity, and acceleration as function of time for the projectile.

    2. Relevant equations

    3. The attempt at a solution

    I've been looking through the time functions but I can't seem to figure out how to write these equations. Any help would be greatly appreciated.
  2. jcsd
  3. Jan 22, 2009 #2


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    It's a projectile motion problem. What is a projectile? An object that, once set into motion (launched) travels solely under the influence of gravity. Gravity is a constant force (it isn't really, but it is for our purposes, unless you're travelling really large vertical distances). So you already know that the acceleration is constant (doesn't change with time). From that you can either work backwards using calculus to find the velocity and position. OR, if you haven't studied calculus, then your teacher will have taught you kinematics formulas that *describe* the motion of an object under constant acceleration (formulas that are derived from calculus), and you can just *use* them.
  4. Jan 24, 2009 #3
    I didn't really understand our teacher when he taught those formulas, is there a place I can look which teaches the formulas i'll need to use?
  5. Jan 24, 2009 #4
    accident put wrong post in this forum
    Last edited: Jan 24, 2009
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