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Final speed of a rotating spaceship!

  1. Mar 15, 2010 #1
    1. The problem statement, all variables and given/known data

    Lets imagine that in the movie 2010. The Discovery is rotating then they find it. Every time the ship reaches a speed in the circular motion of 24000 km/h the engine gives a burst of energy. Which amounts to 20 kN. The mass of the Discovery is 30.000 kg. The time from the engine gives a burst amounted to the above size to the ships engine going to sleep is 3 minutes.
    How do I calculate the extra speed v_final which is achieved by the engine burst after the three minutes. Necletecting all other forces?

    Is there a specific formula?

    According to my book. the answer is suppsed to be 24400 km/h.

    I have to tried to the formula

    [tex] F = 1/2 \cdot m v_f^2 - 1/2 \cdot m v_i^2 [/tex]

    But using that formula I arrive at v_final = v_initial.

    What am I doing wrong?

  2. jcsd
  3. Mar 15, 2010 #2

    Filip Larsen

    User Avatar
    Gold Member

    Your scenario has the information: acceleration force (20 kN), mass (30 ton) and time (180 seconds); and you want to calculate the resulting change of speed. A way forward could be to figure out how force and mass relates to acceleration and how (constant) acceleration relates to change in speed.
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