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Homework Help: Translational Momentum of a particle

  1. Oct 12, 2006 #1
    Suppose that your mass is 80 kg. How fast would you have to run to have the same translational momentum as a 1600 kg car moving at 1.2 km/h? I happen to know the answer is 24 km/hr. But, how do I get to this answer? What are the steps? Could someone solve it out and show me how they got it? Thanks a million!
  2. jcsd
  3. Oct 12, 2006 #2
    Momentum, which we denote by p, is simply the product of the mass and the velocity: p=mv. So since you know the mass and velocity of the car you can calculate its momentum and since you know what your mass is you can calculate what your velocity needs to be in order to have that same momentum.
  4. Oct 12, 2006 #3
    The car's momentum is 1600*1.2 kg-km/hr? That being 1920. What would the units be?
    Now my momentum is 80*Vu kg-km/hr where Vu is your velocity?
    Where do I go from here?
  5. Oct 12, 2006 #4
    Equate the two and solve for Vu. Momentum doesn't have a special unit in the SI system, it's usually just written as kg*m/s or sometimes N*s (the two are equivalent).
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