Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Projectile Motion, With out numbers

  1. Sep 17, 2008 #1
    Projectile Motion, With out numbers :(

    1. The problem statement, all variables and given/known data

    A body is projected at an angle such that the horizontal range is equal to three times the greatest height. find the angle of projection.

    2. Relevant equations
    I dont know


    3. The attempt at a solution

    all i got so far is that vx= v cos(angle) and vy= v sin(angle)

    This is a really tricky question for me and i do not know where to start.
     
  2. jcsd
  3. Sep 17, 2008 #2
    Re: Projectile Motion, With out numbers :(

    You should be able to look in your text for formulas for horizontal range (R) and max height (h). Use thes formulas to write R = 3 h, and then solve for projection angle theta.

    If you don't have these formulas, the problem is a bit longer...
     
  4. Sep 17, 2008 #3

    Dick

    User Avatar
    Science Advisor
    Homework Helper

    Re: Projectile Motion, With out numbers :(

    Split in into components. x(t)=vx*t, y(t)=vy*t-(1/2)*g*t^2. Find the range by figuring out when y(t)=0. The height is where y(t) is a maximum. Where is that?
     
  5. Sep 17, 2008 #4
    Re: Projectile Motion, With out numbers :(

    ah. i got it. thanks so much. my final answer was 53.13 degrees.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook