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Homework Help: Ball vector problem

  1. Sep 14, 2008 #1
    1. The problem statement, all variables and given/known data
    You throw a ball toward a wall at speed 37.0 m/s and at angle θ0 = 43.0° above the horizontal (Fig. 4-35). The wall is distance d = 20.0 m from the release point of the ball. (a) How far above the release point does the ball hit the wall? What are the (b) horizontal and (c) vertical components of its velocity as it hits the wall?


    2. Relevant equations
    V_x = V_0 cos(theta)
    V_y = V_0 sin(theta) - gt

    3. The attempt at a solution

    I was able to find b by using V_x = V_0 cos(theta) with theta being 43 degrees and V_0= 37.
    When I tried to find part a, I thought it was a simple tan association.
    tan (43) = x/20 -> x = 20*tan(43)
    I got x = 18.65... and it was wrong.
    I tried getting part c using V_y = V_0 sin(theta) - gt with:
    V_0 = 37, theta = 43 and g = 9.8
    Then I got stuck.
    Am I doing it right? How do you approach a and c?
  2. jcsd
  3. Sep 14, 2008 #2


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    Staff Emeritus
    Science Advisor
    Homework Helper

    That would work if the ball travelled in a straight line, at constant velocity. But that doesn't happen because of gravity.

    That's good, but you need to find t to finish the question.

    Can you use the horizontal distance and velocity to find t?
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