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Will the comet hit the earth?

  1. Jun 5, 2010 #1
    1. The problem statement, all variables and given/known data
    A comet is observed in a distance of 100 Earth -radius away from the Earth. It is approaching with a speed of 15000 km/h in a direction only 50 off the line connection the two objects.
    Earth mass 5.97*1024 kg
    Earth radius 6.378*106 m
    Gravity constant 6.6726*10-11 Nm2/kg2
    (The geostationary zone is an orbit with radius of 6.62 Earth –radius, and is packed with communication satellites orbiting the Earth.)

    2. Relevant equations
    Will the comet hit the Earth, and if so – when ?
    Will the comet hit the geostationary zone, and if so – when ?

    3. The attempt at a solution
    Don't know what to do?
    Last edited: Jun 5, 2010
  2. jcsd
  3. Jun 5, 2010 #2

    Andrew Mason

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    Science Advisor
    Homework Helper

    Re: Comet

    Try applying Kepler's second law of planetary motion.

    If its orbit barely intersected a) the earth or b) the geostationary zone, how much speed would it have based on Kepler's second law?

    Does it have enough energy to reach such a speed?

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