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Homework Help: Ball Acceleration and Trajectory Question

  1. Mar 17, 2012 #1
    1. The problem statement, all variables and given/known data
    A ball is dropped from a height of 39.0m. The wind is blowing horizontally and imparts a constant acceleration of 1.20 m/s^2 to the ball.
    a. Show that the path of the ball is a straight line and find the values of R and θ (R is the distance on the x-axis from the ball's starting point to the ending point and θ is the angle between the x-axis and the ball's landing point... sorry if that's not clear! It's in the book's diagram and I'm not sure how to get the image here)
    b. How long does it take for the ball to reach the ground?
    c. With what speed does the ball hit the ground?

    2. Relevant equations

    3. The attempt at a solution
    I know that the x acceleration is 1.2 m/s^2 and the y acceleration is 9.8 m/s^2 (should gravity ever be a negative value?) but I'm not sure where to go from there. According to the solutions guide, θ=arctan(9.8/1.2)=83°, which I understand, but I'm not sure how to get the R value, (the solutions guide says R=39.0m/tan(83°) but I'm not sure what equation they used for it). Any help would be appreciated! I'm having trouble with questions with motion in two dimensions because I'm not sure how to approach the questions, so if anyone has any tips, I'd really appreciate that as well :)
  2. jcsd
  3. Mar 17, 2012 #2
    Think of this question as a right triangle. If your bottom angle is 83°, assuming that you have found it already, then it is a simple matter of using the Pythagorean theorem to find R.
  4. Mar 17, 2012 #3
    Thank you so much! I understand that part now.
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