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!

Need help with some kinematics/vectors

  1. Sep 12, 2008 #1
    1. The problem statement, all variables and given/known data
    During World War 1, the Germans had a gun called Big Bertha that was used to shell Paris. The shell had an initial speed of 2.26 km/s at an initial inclination of 65.8 degrees to the horizontal. The acceleration of gravity is 9.8 m/s^2. How far away did the shell hit? Answer in units of km.
    How long was it in the air? Answer in units of s.

    2. Relevant equations
    Vf= Vi + a (tf-ti)
    y= yi + vit + 1/2 at^2.

    3. The attempt at a solution
    I did it several different ways and keep getting answers that are wrong. I got 4.10 s for time, then I got .420s and .840 s. I keep getting the wrong answer. Once I figure out how to do time, I'll be able to do the distance part. Keep in mind the a is in meters per second but kilometers is required in the answer.
  2. jcsd
  3. Sep 12, 2008 #2
    Which of the two eqns did you use to find the time of flight t? What values did substitute?
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Need help with some kinematics/vectors