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!

A projectile problem

  1. Feb 8, 2012 #1
    1. The problem statement, all variables and given/known data

    A cannon is fired at an angle of 30 degrees above the horizontal from a cliff that is 20m above a flat river bottom. What is the initial speed of the projectile if it is found to land 40m from the base of the cliff?



    2. Relevant equations
    g = 9.8ms^-2
    Vi = initial velocity

    3. The attempt at a solution
    I know that Vi cos 30t = 40, but does the "t" represent the time taken for the entire projectile motion, or just the upper symmetrical parabolic trajectory? I'm stuck at Vi cos 30t = 40 because what I did after simply didn't make any sense at all.

    I've been stuck on this question for days on end, please help me with it! Thanks! :D
     
  2. jcsd
  3. Feb 8, 2012 #2
    The [itex]t[/itex] represents the entire time of flight, from your equation you can actually solve for it. Now how about a second equation for the vertical part of the flight?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: A projectile problem
  1. Projectile Problem (Replies: 2)

  2. Projectile problem (Replies: 1)

  3. Problem on projectile (Replies: 6)

  4. Projectile problem (Replies: 3)

  5. Projectile problem (Replies: 1)

Loading...