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Homework Help: Finding Acceleration of Gravity of Fictional Planet

  1. Oct 21, 2009 #1
    In preparation for my upcoming first exam I was doing all of the suggested problems throughout the chapters. Everything was fine until this problem:

    1. The problem statement, all variables and given/known data
    An astronaut on the planet Zircon tosses a rock horizontally with a speed of 6.95m/s. The rock falls through a vertical distance of 1.4m and lands a horizontal distance of 8.75m from the astronaut. What is the acceleration of gravity on Zircon?

    2. Relevant equations
    Distance=speed x time

    3. The attempt at a solution



    Now, I thought this was correct but according to the back of the book the answer is 1.77m/s which would be 1.4*1.26. Am I misunderstanding something?
  2. jcsd
  3. Oct 21, 2009 #2


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    Staff Emeritus
    Science Advisor
    Gold Member

    You found the speed of the rock if it fell at a constant speed. You are meant to find the acceleration of the rock. You need to use an equation that relates time, distance and acceleration.
  4. Oct 21, 2009 #3
    Are you doing projectile motion?
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