1. Limited time only! Sign up for a free 30min personal 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!

Homework Help: Vector Addition: Finding Displacement

  1. Oct 30, 2011 #1
    I am having a lot of trouble with my homework. If anyone could help me, it would be much appreciated.

    The Smith's go on vacation. They travel 16.0 km north/west; then turn 27 degrees to the left and go 135 km; then 294 km south/west. What is their displacement from home?

    So I found the X and Y components (using trig functions) of each vector and added them. I then tried to put those numbers into the Pythagorean theorem, but it's not working. I think my X and Y components are wrong. I got the Xs to equal 69 and the Ys to equal 155.3. This is the diagram I made: (the numbers that were given are in red, the rest I found, not sure if they are right though)
    [PLAIN]http://img257.imageshack.us/img257/7742/78747381.png [Broken]
    By c42711 at 2011-10-30
    Last edited by a moderator: May 5, 2017
  2. jcsd
  3. Oct 30, 2011 #2


    User Avatar
    Homework Helper

    Yes, something wrong with those x y components. The 294 SW vector has x component 294*cos(45) = 208 west. So your total of 69 is way too small. Got your calculator set on degrees? Note that two of the y components are north while the third one is south.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook