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: Intro physics hw help

  1. Jul 17, 2005 #1
    hey everyone, i have a few questions that i just don't understand.
    1) a golfer imparts a speed of 27.0m/s to a ball, it travels the max possible distance b4 landing on the green. the tee and the green are at the same level. a) how much time does the ball spend in the air? b) wat is the longest "hole in one" that the golfer can make, if the ball does not roll when it hits the ground?

    i would really really appreciate ur help and if someone can do these problems can u please give clear solutions?
    thanx alot
  2. jcsd
  3. Jul 17, 2005 #2
    I believe 45 degrees is the angle that produces the longest distance in projectile motion.
  4. Jul 17, 2005 #3


    User Avatar
    Homework Helper

    [tex]y = y_0 + v_{0y}t + \frac{1}{2}a_yt^2[/tex]
    [tex]x = x_0 + v_{0x}t + \frac{1}{2}a_xt^2[/tex]
    Both equations (especially the latter) reduce quite nicely with some logical thinking (what sort of velocity has an effect on the time?). Then just put the equations together and find the maximum (hint: derivate). Quickly done: 45 degrees does look like the correct answer. Now just throw the angle into the (reduced) equation you got in the first step.
    Hint: Express [itex]v_0[/itex] in [itex]v_{0y}[/itex] and [itex]v_{0x}[/itex]

    b) You already got the equation you need in a). Now just throw the velocity in and you're done.
    Last edited: Jul 17, 2005
  5. Sep 11, 2005 #4
    thanks that also just helped me
  6. Sep 11, 2005 #5
    but i simply used the equation for range to find longest
    distance which is same as X, R=X= Vox*T,
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook