1. Not finding help here? Sign up for a free 30min 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!


  1. Nov 15, 2007 #1

    1. A ball is launched with a velocity of 1000m/s at some angle theta. The ball must travel 2000m in the x dir and land 800m in the y dir on a plateau. What theta should the ball be shot at to make this happen.

    2. y=y0 +v0t -.5gt^2

    3. I solved for t using x=v0cos(theta)t and plugged that into the y equation and got one solution. The answer key says theres two solutions. One at 20 something, which is the one i got and also one at 89.4 degrees. Can someone show me how to get the other/both solutions

    THANKS!!!!!! I appreciate it
  2. jcsd
  3. Nov 15, 2007 #2
    You should use the formula
    y=x tan theta - [tex]\stackrel{gx^2}{2u^2cos^2 theta}[/tex]

    THis formula is combined by
    verticial component using s=ut+1/2 at^2
    horizontal component v=s/t
  4. Nov 15, 2007 #3
    i used that equation and still only got 22.4 degrees at the sole solution.... 89.4 doesnt seem to fit. Is there an error in the answer key?
  5. Nov 15, 2007 #4
    i also get the 22.4 degree
    but it is acceptable that there is another angle is the answer.....
    however I forget how to solve it ~sorry
  6. Nov 15, 2007 #5
    ok thanks anyway!
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Projectile Motion PLEASE HELP MIDTERM TOMMOROW