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: Simple dynamics question, answer seems incorrect...

  1. Jul 14, 2016 #1
    1. The problem statement, all variables and given/known data

    2. Relevant equations
    V= Vg*cos θ

    3. The attempt at a solution
    Is this solution correct. I did everything the same, but I did not use the 15 ft/s.
    Since An= (v^2/ρ) with V being the velocity in the t direction. The 15 ft/s according to me is only the component of V that is in the y direction of a normall x-y plane.
    So to get the velocity in the tangential direction of the path, so the full V. You need to do 15 ft/s / cos θ?
    That they use Vg as V in the equation for An is wrong?
  2. jcsd
  3. Jul 14, 2016 #2


    User Avatar
    Homework Helper
    Gold Member
    2017 Award

    Apparently the 15 ft/s given in the problem is meant to be the tangential speed. "Downward" is just meant to indicate that the boy is "swinging down" at this instant.

    I understand how you interpreted it, and you would be correct for your interpretation. The wording of the statement of the problem could have been better.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted