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: Angle of Football Kickoff

  1. Sep 11, 2010 #1
    1. The problem statement, all variables and given/known data

    Two footballs, A and B, are kicked from level ground with identical initial speeds, but with θA greater than θB.
    Which football reaches a higher elevation?
    Which football travels farther?
    Which football stays in the air longer, i.e., has the greater hang time?
    Which football has the greater horizontal component of velocity?

    2. Relevant equations

    vx0=v0cos(angle)
    vy0=v0sin (angle)
    t=vy0/g
    y=((vy0^2)-vy^2)/g
    x=vx0*t
    3. The attempt at a solution

    I thought the answers were Football A, Football B, Football A, and then Football B, but these were wrong. I did a plug-in for this problem and I used 60 degrees for Angle A and 50 for Angle B with an initial velocity of 20 m/s. When I did all of the calculations out, I got the results I said above.
     
  2. jcsd
  3. Sep 11, 2010 #2
    Your answers are right, although i would like to know the text answers. Could you please post them?
     
  4. Sep 11, 2010 #3

    PhanthomJay

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Try using Angle A =45 degrees and Angle B =0 degrees. Which one travels farther? The question is missing information.
     
  5. Sep 11, 2010 #4
    There is an option that says "depends on the angle."
     
  6. Sep 11, 2010 #5

    PhanthomJay

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    I like that option:wink:
     
  7. Sep 12, 2010 #6
    so since every equation above contains a vy0 or vxo, that would means that each answer is dependent on the angle?
     
  8. Sep 12, 2010 #7

    PhanthomJay

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    No. Look at the last one, for example.
    They both have the same initial velocity at angle A or B. Which one would have the greater x component of the initial velocity?
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook