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!

Water Rocket

  1. Nov 2, 2008 #1
    1. The problem statement, all variables and given/known data
    Hi, guys.
    I did a project but questions are killing me right now.
    I was going all the tutorials but I really have no idea.
    What we did was water rocket project.
    Here are the data
    Ttotal - avg. 9.96 sec.
    Avg. Apogee - 2.94 sec.


    2. Relevant equations



    3. The attempt at a solution


    I need to find the v initial, ymax, and the maximum range.
    Here is how I did it

    For Vinitial
    DeltaY(0) =(Vinitial)(5.88)+(1/2)(-9.8)(5.88)^2
    Vinital = 28.8m/s
    5.88sec comes from avg. apogeeX2 ------> (2.94)(2)

    For Ymax,
    Ymax= (Vinital)(time)+(1/2)(-9.8)(time)
    (28.8)(2.94)+(1/2)(-9.8)(2.94)^2
    = 42.3 m

    For maximum Range,
    I found out that cos 45 will give me maximum range so

    Range=(Vinital)(cos45)(time)
    (28.8)(cos45)(5.88)
    = 119.7 m

    Lastly, my teacher asked, "What role does the water play in making the rocket move?"
    He also asked for relevent formulas and a diagram illustrating the forces.
    Only thing we learned so far are Horizontal Projectil motion and free fall.
    I do not think we ever learned this.
    Can you please help me with this? Ive been working for entire day!!
    Thanks guys.
     
    Last edited: Nov 2, 2008
  2. jcsd
  3. Nov 2, 2008 #2
    Oh, I realized I had to put what I did.
    here is what I did..
    for Vinitial,
    I did
    deltaY=(Vinitial)(5.58)+(1/2)(-9.8)(5.88)^2
    and got Vinitial=28.8m/s.
    5.88 comes from avg. apogee= 2.94X2=5.58

    For Ymax,
    I did
    Ymax = (28.8)(2.94)+(1/2)(-9.8)(2.94)^2
    Ymax = 42.3 m

    Lastly, for Range
    Since Range max, I found that cos 45 will give me maximum range
    So,
    Range=(Vinital)(cos45)(time)
    (28.8)(cos45)(5.88)
    Range=119.7m.

    Here is how i did it.
    But honestly,
    on the last problem with "what role does the water play in making the rocket move?"
    I abs. have no idea.
    Thanx guys.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Water Rocket
  1. The Rocket Equation (Replies: 5)

  2. Multistage Rocket (Replies: 0)

  3. Relativistic Rocket (Replies: 14)

  4. Rocket Launching (Replies: 1)

  5. Rocket momentum (Replies: 1)

Loading...