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Homework Help: Im not sure if this is the correct formula for this question, corect me

  1. Apr 15, 2007 #1
    Im not sure if this is the correct formula for this question, plz corect me

    1. The problem statement, all variables and given/known data
    hi this is the problem: the burning of the second stage of a two stage toy rocket takes the rocket from 12 m/s to 40 m/s in 5.0s. How far does the rocket during this time?

    2. Relevant equations
    would i use delta t= delta v/a ?
  2. jcsd
  3. Apr 15, 2007 #2
    Yes, you would need to use that equation.
  4. Apr 15, 2007 #3
    Thanks neutrino.. but would i do (40-12) to find the velcoity?
  5. Apr 15, 2007 #4
    What are the 'knowns' in [tex]\Delta t = \frac{\Delta v}{a}[/tex]? Substitute them and find the unknown.
  6. Apr 15, 2007 #5
    the knowns are velocity and acceleration, yeah i know that you substitute them but would i do (40-12) to find the velcoity?
    so like for (40-12) do i plug that in velocity together?
    Last edited: Apr 15, 2007
  7. Apr 15, 2007 #6
    Are you sure about that?

    Delta v is change in velocity = Final velocity - Initial Velocity = 40-12.
  8. Apr 15, 2007 #7
    Yeah, so it's 23 but i was just saying...how would i put that in the formula in the proper way...

    delta t= delta v/a, delta t= (40-12)/5.0s, delta t =28m/s /5.0s = 5.6s
    therefore the rocket traveled for 5.6 s?
  9. Apr 15, 2007 #8
    Units are important physics, and the Second is a unit of time.

    It has already been stated in the problem that the rocket has been moving for 5 seconds when it's speed changed from 12 to 40 m/s. Acceleration is a measure of how velocity changes with time.
  10. Apr 15, 2007 #9
    Okay...thanks for taking your time :rolleyes:
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