Results 1 to 2 of 2

Math Help - football hangtime.

  1. #1
    Senior Member
    Joined
    Jan 2007
    Posts
    476

    football hangtime.

    could i use trig with this? to find the x0? then use one of the common physics 'formulas to find time?

    appreciate any help please.

    A punter on a football team tries to kick a football so that it stays in the air for a long "hang time."
    the ball is kicked with an initial velocity of 25.0 m/s at an angle of 58.5 above the ground, what is the "hang time"?
    s
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Forum Admin topsquark's Avatar
    Joined
    Jan 2006
    From
    Wellsville, NY
    Posts
    9,672
    Thanks
    302
    Awards
    1
    Quote Originally Posted by rcmango View Post
    could i use trig with this? to find the x0? then use one of the common physics 'formulas to find time?

    appreciate any help please.

    A punter on a football team tries to kick a football so that it stays in the air for a long "hang time."
    the ball is kicked with an initial velocity of 25.0 m/s at an angle of 58.5 above the ground, what is the "hang time"?
    s
    It's not so much an equation as a method.

    Set up the following coordinate system:
    Place an origin where the football starts and let the +x direction be in the horizontal direction of the ball and +y be straight up.

    Presuming the football starts on the ground and ends on the ground we have the following information:
    x_0 = 0~m and y_0 = 0~m
    x = ? and y = 0~m
    v_{0x} = 25.0 \cdot cos(58.5^o)~m/s and v_{0y} = 25.0 \cdot sin(58.5^o)~m/s
    a_x = 0~m/s^2 and a_y = -9.8~m/s^2

    We want an equation for t. It looks like
    y = y_0 + v_{0y}t + \frac{1}{2}a_yt^2
    will do the trick:

    0 = 0 + 25 \cdot sin(58.5^o)~t - 4.9t^2 <-- Divide through by t

    0 = 25 \cdot sin(58.5^o) - 4.9t

    t = \frac{25~sin(58.5^o)}{4.9} = 4.73707~s

    -Dan
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. 10 football matches.......
    Posted in the Discrete Math Forum
    Replies: 3
    Last Post: October 30th 2009, 08:51 AM
  2. football tournament
    Posted in the Discrete Math Forum
    Replies: 1
    Last Post: October 4th 2009, 07:53 AM
  3. Football Fixtures Help
    Posted in the Math Puzzles Forum
    Replies: 6
    Last Post: August 30th 2009, 12:24 AM
  4. Geometry in a Football
    Posted in the Geometry Forum
    Replies: 7
    Last Post: July 23rd 2009, 08:02 PM
  5. Football game
    Posted in the Discrete Math Forum
    Replies: 11
    Last Post: June 8th 2008, 11:03 PM

Search Tags


/mathhelpforum @mathhelpforum