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!

2D Kinematics Question

  1. Sep 17, 2009 #1
    1. A delivery truck travels 10 km north, 18 km east, and 29 km south.

    a) What is its final displacement in km from the origin.

    b) What is the angle in degree of the final displacement relative to the east.

    2. I used the pythagorean theorem to obtain the final displacement from the origin. Then using the displacement found obtained the angle using sign 90 degrees.

    3. First I drew an x/y coordinate system. The origin was at 0. Drew a line going 10 km north, 18 km east and 29 km south which puts me 19 km below the origin line.

    18^2+19^2=685
    The square root of 685 was 26.17 which was the final displacement from the origin.

    For the angle, I calculated 26.17sin90 degrees which equaled 26.17. According to the online hw system, both answers were wrong.

    What did I do wrong? Please advise. I am completely lost in physics so far.
     
  2. jcsd
  3. Sep 17, 2009 #2

    rl.bhat

    User Avatar
    Homework Helper

    Your calculation of the direction is wrong. You have net x displacement and y displacement. Then tanθ = y/x will give you the direction.
     
  4. Sep 17, 2009 #3
    Hi rl.bhat,

    Physics is completely foreign to me. Please elaborate. If I use tan(theta)=y/x, what do I plus in for y and x? Also, how can I find final displacement (in km) from the origin?
     
  5. Sep 17, 2009 #4

    rl.bhat

    User Avatar
    Homework Helper

    In the given problem x = 18 km and y = - 19 km.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: 2D Kinematics Question
  1. 2D kinematic questions (Replies: 4)

  2. 2D Kinematics question (Replies: 3)

  3. 2D Kinematics Question (Replies: 6)

Loading...