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!

Homework Help: 1d Motion

  1. Sep 17, 2005 #1
    2d Motion

    I've been stuck with this problem for a while. Appreciate if anyone can point me in the right direction.

    A boy stands in a field, he throws a stone with an initial 45 degree angle. The field has a 5 degree angle downwards, so the stone touches down at -5 degree angle and 82 meters away. g=9,8m/s^2

    Find the time (t) for the entire throw, and the initial velocity (v0) for the stone.
    Last edited: Sep 17, 2005
  2. jcsd
  3. Sep 17, 2005 #2

    4 equations for 4 unknows

    we use the symmetry of the motion, and the independence of the motions in different directions
  4. Sep 17, 2005 #3
    sorry, cos50 and sin50 above mean cos5 and sin5
  5. Sep 17, 2005 #4
    and you can also use energy , but i don't think it woulb be much more easier
  6. Sep 17, 2005 #5
    couldn't i do: R=Vi^2*sin2(THETAi)/g

    R=the length of the throw

    Solving for Vi= 21.72 m/s
  7. Sep 18, 2005 #6
    And then set up an integral for time?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook