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!

Max height of a baseball

  1. Mar 25, 2007 #1
    1. The problem statement, all variables and given/known data
    Estimate the maximum height reached by a baseball during its flight if it is thrown with a velocity of 81 feet per second at an angle of 75 degrees relative to level ground.


    3. The attempt at a solution
    I found an answer, but I don't know if I did it right so I guess I'm just asking for someone to check it.

    I found x = (81cos 75)T and y = -16T^2 + (81sin 75)T
    So I put that in my calculator in parametric mode and graphed it with the right window. I got that the highest it would reach is 95.62ft when T=2.4

    Is that right?
     
  2. jcsd
  3. Mar 25, 2007 #2

    radou

    User Avatar
    Homework Helper

    The answer you got doesn't look right. Could you show how you got that result?
     
  4. Mar 25, 2007 #3
    <.< I used my calculator with that information, guessed at different T values and found that when T was 2.4, it was the highest?

    I don't know what else to show you...
     
  5. Mar 25, 2007 #4

    radou

    User Avatar
    Homework Helper

    Didn't you use any equations? What does the y-component of the velocity equal when the ball is as its highest point? What does that tell you about the time?
     
  6. Mar 25, 2007 #5
    What are you talking about? I gave you the equations I used...
     
  7. Mar 25, 2007 #6

    radou

    User Avatar
    Homework Helper

    Where did you get this from?
     
  8. Mar 25, 2007 #7
    That's gravity...or something.

    There was a similar example my math book and I just substituted the different angle and velocity.
     
  9. Mar 25, 2007 #8

    radou

    User Avatar
    Homework Helper

  10. Mar 25, 2007 #9
    I still don't know if that's right or what to do/how to fix it if it's wrong...
     
  11. Mar 25, 2007 #10

    cristo

    User Avatar
    Staff Emeritus
    Science Advisor

    Have you read the page that radou provided in the link above. Again, how did you come up with the equation for the vertical distance?

    Also, I would strongly recommend against using a calculator to perform these calculations for you. You should be able to do it by hand; and if not, now's a good time to learn how to!
     
  12. Mar 25, 2007 #11
    Yes, I read the link. I found the equations by an example in my math book.

    This is the example:
    Kevin hits a baseball at 3ft above the ground with an initial speed of 150ft/sec at an angle of 18 degrees with the horizontal. Will the ball clear a 20-ft wall that is 400 ft away?

    The path of the ball is modeled by the parametric equations x = (150 cos 18)t, y = -16t^2+(150 sin 18)t + 3

    ---
    I used that example and substituted the numbers. That's the only way I could figure out the problem.
     
  13. Mar 25, 2007 #12

    hage567

    User Avatar
    Homework Helper

    The answer you found seems right. I don't know how detailed a solution you are looking for, if you don't know the physics behind the motion. Does your book not explain it?
     
  14. Mar 25, 2007 #13

    cristo

    User Avatar
    Staff Emeritus
    Science Advisor

    Oh I see, your book uses imperial units (for some strange reason), so that would explain why g=16!

    Still, I stand by my comment that you should not rely on a calculator for this problem. Surely you must have done some theory before you come across the example in the text book.
     
  15. Mar 25, 2007 #14
    That's all the my book explains...so it's not all that helpful. Our teacher isn't that helpful either. =S

    If you can do it another way and get the same answer, that's good enough that I'll leave my work how it is...
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Max height of a baseball
  1. Max/ min (Replies: 3)

  2. Height problem (Replies: 3)

  3. Difference in heights (Replies: 12)

Loading...