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Homework Help: Projectile Motion

  1. Sep 18, 2008 #1
    1. The problem statement, all variables and given/known data

    On the surface of the moon, an astronaut jumps with a speed of 1.0 m/s at an angle of 30 degres above the horizon. A max height of .78 m is reached.

    a- What is the acceleration of gravity on the moon?
    b- Determine the horizontal range.
    c- How much time did this displacement take?

    2. Relevant equations

    at/2 = v initial (sin angle)

    displacement =((v initial) ^2 (sin angle))/a

    ymax = (v initial)^2 / 2a

    3. The attempt at a solution
    question a-
    2a(.78m) = 1)(1/2)

    acceleration is .064 m/s^2

    question b-
    displacement = (1)(sin 60)/.064
    displacement = 13.53 m

    question c-
    t = .5 m/s / .032 m/s^2
    t = 15.62 s

    Have I made a mistake? I thought gravity on the moon was 1.6 m/s^2, and my teacher usually uses examples that work out correctly.
  2. jcsd
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