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!

Spring launched

  1. Jul 17, 2013 #1

    Zondrina

    User Avatar
    Homework Helper

    1. The problem statement, all variables and given/known data

    A spring is launched from the ground at 2.3 m/s t an angle of 78° to the ground. What is the max height of the spring? How far did the spring travel?

    2. Relevant equations

    ##\vec{v}_R = 34 m/s##
    ##\theta = 78°##

    3. The attempt at a solution

    First things first, get my components :

    ##\vec{v_v} = 34sin(78°) = 33.3 m/s [Up]## [ Vertical velocity ].
    ##\vec{v_H} = 34cos(78°) = 7.1 m/s [Forward]##

    Hmm looks like I need time. So lets use ##\vec{Δd}_V = \vec{v_v}Δt - (4.9)(Δt)^2##. We know that the overall vertical displacement will be 0 because the spring returns to rest due to gravity. So simplifying :

    ##0 = (33.3 - 4.9Δt)Δt##

    So either ##Δt = 0## which we know we can throw out, or ##Δt = \frac{-33.3}{-4.9} = 6.8 s##.

    Now we know how long the spring was in the air. So because of acceleration due to gravity, we know that the max height of the spring will be achieved at ##Δt_S = Δt/2 = 3.4 s##.

    To find the actual maximum height we calculate :

    ##\vec{Δd}_V = \vec{v}_v Δt_S - (4.9)(Δt_S)^2 = (33.3)(3.4) - (4.9)(3.4)^2 = 56.58 m/s [Up]##

    To find out how far the spring traveled in total, another small calculation :

    ##\vec{Δd}_H = \vec{v}_H Δt = (7.1)(6.8) = 48.3 m [Forward]##.

    I think that should be it. Loving these word problems.

    EDIT : Just noticed this should be in intro phys, I must have clicked adv by accident. If a mod could move it there it would be appreciated.
     
  2. jcsd
  3. Jul 17, 2013 #2

    Dick

    User Avatar
    Science Advisor
    Homework Helper

    I'm not sure why your statement says velocity 2.3m/s and you finally used 34m/s. But other than that it looks pretty ok.
     
  4. Jul 17, 2013 #3

    Zondrina

    User Avatar
    Homework Helper

    Oh wow haha. Been awake since 5am, taking its toll i guess, but these word problems are too fun to solve.

    Quantifying the physical.

    Okay though, as long as the process is fine, that's all I really care for.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Spring launched
  1. Rocket Launching (Replies: 1)

Loading...