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Homework Help: Momentum attained by a laser beam

  1. Nov 17, 2009 #1
    A small spaceship, with a mass of 1500 kg (including occupants), is at rest in outer space with negligible gravitational forces acting on it. If the astronaut turns on a 10kW laser beam that points out of the ship into the deep of space, what speed will the ship attain in 1 day because of the momentum carried away by the beam?

    10000*60*60*24= 864000000J
    v= 1073.31

    where do i go from here?
  2. jcsd
  3. Nov 17, 2009 #2


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    What's the equation for the momentum of a photon and it's energy.
    How many photons/second of this momentum can you generate from this laser power
  4. Nov 17, 2009 #3
    p= h/ lamda
    E= hc/ frequency
    play with these formulas by sub. then you should get it.. by the way the p=momentum
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