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: Unit Vector Velocity

  1. Sep 15, 2009 #1
    1. The problem statement, all variables and given/known data
    Exactly 2.9 seconds after a projectile is fired it has the velocity (9.0i +4.5j) m/s.
    What is the horizontal range of the projectile.

    2. Relevant equations

    3. The attempt at a solution
    Range = [((9.0i^2 + 4.5j^2)^1/2)^2 x sin2(arctan(4.5/9))]/ 9.8 m/s/s
    Range = 8.3 m but this is incorrect.
  2. jcsd
  3. Sep 15, 2009 #2

    D H

    User Avatar
    Staff Emeritus
    Science Advisor

    Of course that's not correct. Look at the units, for one thing. For another, you aren't accounting for that 2.9 seconds.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook