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!

2D projectile motion problem

  1. Feb 18, 2013 #1
    1. The problem statement, all variables and given/known data
    A Projectile is launched from the top of a 100m tower and falls 20m below the bottom of the tower and 90m away in the x direction. Time of flight is 6 seconds.

    1. Find the x component of the velocity of the object when it strikes the ground.

    2. Find the y-component of the inital velocity of the object.

    2. Relevant equations
    I tried using Δx=Vi,x(t) to solve for the x component of Vf (since the inital should be the same as the final). Then I did the same thing for the y component of Vi.

    3. The attempt at a solution
    I got 15m/s for the x component of Vf and I'm not sure if this is correct. For the y component of Vi I solved and got 20m/s. I used -120m for Δy and i'm not sure if this is right because in the picture it shows the projectile going up a little before it begins to go down 120m.

    Any input would be greatly appreciated :smile:
  2. jcsd
  3. Feb 18, 2013 #2
    Yo I got 15m/s for x. My y was wrong sorry.
  4. Feb 18, 2013 #3


    User Avatar

    Don't forget that the y component of velocity is affected by gravity.
  5. Feb 18, 2013 #4
    What did you end up getting for the y?
  6. Feb 18, 2013 #5


    User Avatar
    Homework Helper

    How is the displacement along y related to the time of flight?

  7. Feb 18, 2013 #6
    Yo i got this problem too. Is vy 9.43m/s?
  8. Feb 18, 2013 #7


    User Avatar
    Homework Helper


  9. Feb 18, 2013 #8
    Awesome thanks!
  10. Feb 18, 2013 #9
    I got it. Wow, I don't know how I missed that. Maybe my brain was overloaded from studying all day and just farted. Thanks, though!
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook