1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Kinematics question needed to be solved. Help please

  1. Oct 15, 2011 #1
    1. The problem statement, all variables and given/known data

    A basketball is being thrown at the hoop (3.0m high) from 4.0 meters away. If the initial height of the ball is at 1.5m with an initial velocity of 3.0 m/s, at what angle should the ball be thrown? (Assume that air resistance is zero, and gravity = 9.81 m/s^2)



    2. Relevant equations

    This is a kinematics problem. Even my teacher has trouble solving it. Please help. The main formulas are:

    xf = x0 + Vx t + 1/2 a t^2

    yf = y0 + Vy t + 1/2 a t^2


    3. The attempt at a solution

    By using the above two formulas, we came up with a quadratic equation involving tan() and cos() functions. We can't go further. Anyone suggestions?

    12 tan(x) - 8.72(1/cos(x))^2 = 1.5

    Let x be the starting angle of the ball being being thrown (above the horizontal)

    Note: you can't just throw the ball to the hoop in a straight line, you will hit the hoop instead.
     
    Last edited: Oct 15, 2011
  2. jcsd
  3. Oct 15, 2011 #2
    if you show how you got the equation someone can help you.
     
  4. Oct 15, 2011 #3

    Redbelly98

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    Welcome to Physics Forums.

    Okay, but a would be zero in the xf equation.

    I get almost the same thing, except that I have 4tan(x) instead of 12tan(x).

    It's probably easiest to use a graphing calculator to solve the equation at this point. You only need to consider x between 0° and 90°, of course.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Kinematics question needed to be solved. Help please
Loading...