Results 1 to 2 of 2

Math Help - Precal help.. word problem w/ vectors

  1. #1
    Newbie
    Joined
    Mar 2010
    Posts
    6

    Exclamation Precal help.. word problem w/ vectors

    okay here's the problem:
    The magnitude and direction of two forces acting on an object are 70 pounds, S56E, and 50 pounds, N72E, respectively. Find the magnitude, to the nearest hundreth of a pound, and the direction angle, to the nearest tenth of a degree, of the resultant force.

    how do i find the magnitude and the direction angle?

    everytime i sketch out the graph, it turns out weird. i do not understand this at all and when i do get an answer, it is incredibly different than the answer in the back.

    Answer:108.21 lbs ; S 77.4E
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    skeeter's Avatar
    Joined
    Jun 2008
    From
    North Texas
    Posts
    12,108
    Thanks
    970
    Quote Originally Posted by needmathhelptoujours View Post
    okay here's the problem:
    The magnitude and direction of two forces acting on an object are 70 pounds, S56E, and 50 pounds, N72E, respectively. Find the magnitude, to the nearest hundreth of a pound, and the direction angle, to the nearest tenth of a degree, of the resultant force.

    how do i find the magnitude and the direction angle?

    everytime i sketch out the graph, it turns out weird. i do not understand this at all and when i do get an answer, it is incredibly different than the answer in the back.

    Answer:108.21 lbs ; S 77.4E
    directions relative to the + x-axis (east)

    R_x = 50\cos(18) + 70\cos(-34)

    R_y = 50\sin(18) + 70\sin(-34)

    magnitude, |R| = \sqrt{R_x^2 + R_y^2}

    direction, \theta = \arctan\left(\frac{R_y}{R_x}\right)
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Vectors/Tension Word Problem Help
    Posted in the Pre-Calculus Forum
    Replies: 2
    Last Post: May 19th 2011, 02:06 PM
  2. Vectors: Word Problem
    Posted in the Algebra Forum
    Replies: 3
    Last Post: June 7th 2010, 05:41 AM
  3. Bearing/Navagation PreCal Problem
    Posted in the Trigonometry Forum
    Replies: 2
    Last Post: September 4th 2008, 05:09 PM
  4. word problem (tangent vectors)
    Posted in the Calculus Forum
    Replies: 3
    Last Post: July 7th 2008, 01:29 PM
  5. Precal app problem
    Posted in the Math Topics Forum
    Replies: 6
    Last Post: October 13th 2007, 09:43 PM

Search Tags


/mathhelpforum @mathhelpforum