Results 1 to 5 of 5
Like Tree2Thanks
  • 1 Post By skeeter
  • 1 Post By skeeter

Math Help - trig identitities applied question

  1. #1
    Newbie
    Joined
    May 2012
    From
    kanaida
    Posts
    17

    trig identitities applied question

    An object is propelled upward at an angle theta, 45 degree < theta <90 degree, to the horizontal with an initial velocity of v0 feet per second from the base of an inclined plane that makes an angle of 45 degree with the horizontal. If air is ignored, the distance R that it travels up the inclined plane is given by:
    R= v0square square root of 2/16 multiplied by [cos(theta)(sin(theta)-cos(theta)]....Show R(THETA)

    i really dont know how to solve this....this is really advanced and i need help with this
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    skeeter's Avatar
    Joined
    Jun 2008
    From
    North Texas
    Posts
    11,621
    Thanks
    426

    Re: trig identitities applied question

    Quote Originally Posted by koolaid123 View Post
    An object is propelled upward at an angle theta, 45 degree < theta <90 degree, to the horizontal with an initial velocity of v0 feet per second from the base of an inclined plane that makes an angle of 45 degree with the horizontal. If air is ignored, the distance R that it travels up the inclined plane is given by:
    R= v0square square root of 2/16 multiplied by [cos(theta)(sin(theta)-cos(theta)]....Show R(THETA)
    show what?
    Thanks from topsquark
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Forum Admin topsquark's Avatar
    Joined
    Jan 2006
    From
    Wellsville, NY
    Posts
    9,664
    Thanks
    298
    Awards
    1

    Re: trig identitities applied question

    Quote Originally Posted by koolaid123 View Post
    R= v0square square root of 2/16 multiplied by [cos(theta)(sin(theta)-cos(theta)]....Show R(THETA)
    For clarification, you are being asked to prove the above formula?
    R= v_0^2 \sqrt {2/16} \cdot [cos(\theta) \left ( sin(\theta)-cos(\theta) \right ) ]

    This is confusing if R is a range. The units are all wrong. Please give us more information.

    -Dan

    PS Nope. Either R(theta) isn't the range or your answer is incorrect.
    Last edited by topsquark; November 19th 2012 at 03:21 PM.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor
    skeeter's Avatar
    Joined
    Jun 2008
    From
    North Texas
    Posts
    11,621
    Thanks
    426

    Re: trig identitities applied question

    R= v0square square root of 2/16 multiplied by [cos(theta)(sin(theta)-cos(theta)]
    assuming R is the distance from launch to impact up the 45 degree incline ...

    \Delta x = v_0 \cos{\theta} \cdot t = \frac{R\sqrt{2}}{2}

    t = \frac{R\sqrt{2}}{2v_0\cos{\theta}}



    \Delta y = v_0 \sin{\theta} \cdot t - 16t^2 = \frac{R\sqrt{2}}{2}

    v_0 \sin{\theta} \cdot \frac{R\sqrt{2}}{2v_0\cos{\theta}} - 16\left(\frac{R\sqrt{2}}{2v_0\cos{\theta}}\right)^  2 = \frac{R\sqrt{2}}{2}

    \tan{\theta} - \frac{8R\sqrt{2}}{v_0^2\cos^2{\theta}} = 1

    R = \frac{v_0^2 \sqrt{2} \cdot \cos^2{\theta}(\tan{\theta} - 1)}{16}

    R = \frac{v_0^2\sqrt{2} \cdot (\cos{\theta}\sin{\theta} - \cos^2{\theta})}{16}
    Thanks from topsquark
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Forum Admin topsquark's Avatar
    Joined
    Jan 2006
    From
    Wellsville, NY
    Posts
    9,664
    Thanks
    298
    Awards
    1

    Re: trig identitities applied question

    Oops! I solved for x, not R.

    And the units are part of the 16. (I typically leave this as g/2.)

    Thanks skeeter!

    -Dan
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. [SOLVED] An Applied Trig/Max and Min Problem
    Posted in the Calculus Forum
    Replies: 7
    Last Post: January 10th 2012, 11:13 PM
  2. Applied pure trig question
    Posted in the Trigonometry Forum
    Replies: 2
    Last Post: February 8th 2010, 06:47 AM
  3. Applied tr!ig question
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: February 4th 2010, 07:27 AM
  4. Applied trig problem
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: December 19th 2009, 05:02 AM
  5. Applied Statistics question
    Posted in the Statistics Forum
    Replies: 8
    Last Post: July 20th 2009, 08:33 PM

Search Tags


/mathhelpforum @mathhelpforum