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Pushy Astronaut

  1. Apr 11, 2005 #1
    Pushy Astronaut

    a) An astronaut of mass 70 kg pushes off a satellite of mass 420 kg, exerting a force of 120 N for the 0.83 s they are in contact. What is the speed of the astronaut after they have separated?
    vastronaut = m/s

    HELP: Remember Newton's Third Law. The astronaut exerts a force on the satellite. What is the force that the satellite exerts on the astronaut?
    HELP: Apply F = ma. You can figure out the force from the Third Law. You know the mass so you can find the acceleration. Once you know that, apply kinematics to find the speed.

    b) What is the speed of the satellite after they have separated?
    vsatellite = m/s

    c) How far apart are they after 1 minute?
    D= m

    I request some intial help with these parts thanks,
  2. jcsd
  3. Apr 11, 2005 #2
    I know you know the basics of energy, thats all you need for these problems.

    edit: not energy, momentum. im stupid.
    Last edited: Apr 11, 2005
  4. Apr 11, 2005 #3
    Impulse 'J' = Force * Delta t, Is this right

    Impulse = Change in Momentum = mv-MV

    Given: Force = 120 N , delta t = 0.83 seconds.

    m - mass of the astronaut = 70 kg
    M - mass of the satellite = 420 kg

    To find: Speed of the astronaut v_astronaut ( in m/s)

    mv-MV = 120 * 0.83 = 99.6 Ns

    Then what,,.......
  5. Apr 11, 2005 #4
    [tex] Ft = mv [/tex]

    F = 120, t = 0.83. The same force is applied to both the rocket and the ship. So then:

    [itex] v = \frac{Ft}{m} [/tex] for each component.
  6. Apr 16, 2005 #5
    Thanks, whozum, I finally got them all.!
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