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Homework Help: A rocket is launched kinematics

  1. Oct 1, 2008 #1
    1. The problem statement, all variables and given/known dataa 1000kg weather rocket is launched straight up, the rocket motor provides a constant accerelation for 16s, then the motor stops. the rocket altitude 20s after launch is 5100m you can ignore any effects of air resistance.

    what is the rocket's acceleration during the first 16s

    2. Relevant equations

    delta x= xi+viT+1/2aT^2

    3. The attempt at a solution

    just checking my answer since there isn't one in the back of the book.. so this is what i did

    1. i first found the distance of the 4s after the motor stop

    t=4s a=-9.8m/s^2 Vf=0
    so i found Vi

    2. then i use thosenumbers and plugged it into the 1st equation


    therefore the total distance travelled in the first 16s is 5100-2m = 5098m

    3. then i took the 2nd equation and plugged in that to find the accleration


    Did i get the right answer?
  2. jcsd
  3. Oct 1, 2008 #2


    User Avatar
    Homework Helper

    Hi Jennifer001,

    You did not square the 39.2 m/s here.
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