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: Dependent motion with ropes question

  1. Mar 3, 2012 #1
    1. The problem statement, all variables and given/known data
    I attached the problem with my attempt. I think the geometry I used is correct but I am getting the wrong answer. When I take the flip Va/V (as shown in my attempt) I get the right answer. I am not even sure if I can relate velocity with a triangle.

    The method I used is based on the fact that Sa + Sb = L1 so when you take the time derivative you get Va = -Vb.

    Attached Files:

  2. jcsd
  3. Mar 3, 2012 #2


    User Avatar
    Homework Helper

    X=SA cos(theta). As X increases in the rate of 1.5 m/s, both SA and theta change. It is not true that V=VA.

    Write out YB in terms of X, and find the derivative with respect the time.

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook