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Homework Help: Projectile Motion Problem!

  1. Sep 14, 2010 #1
    1. I got the first part right but I cannot figure out how to do the second part!! Help please! And thank you!

    Volcanoes on the Earth eject rocks at speeds of up to 170 m/s. Consider a 1750 m high volcano which ejects rocks in all directions. What is the maximum height above sea level reached by rocks?
    Answer: 3.22*10^3m

    part B: Consider a rock ejected an angle of 30degrees. How far from the axis of the volcano (horizontally) will it strike the ocean?
  2. jcsd
  3. Sep 14, 2010 #2
    separate your x and y components

    t= from y

    v0y =170sin30
    a =-9.81m/s^2
    y = -1750m
    t =
    solve for t using y=v0*t+(1/2)at^2
    then plug t into your x component to get x

    (make sure to keep your initial y velocity positive and your acceleration and y distance negative)
  4. Sep 10, 2012 #3
    Hi, Iam currently working on a similar problem and I keep getting it wrong. I found t to equal 17.34s or 3.57s by using the quadratic formula i then took a time and plugged it back into the formula using all the x component numbers and got 2429.14m or 4084.41m both are wrong.

    my volcano is 2000m high and rocks are shooting at 45 degree angle traveling at 170m/s.
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