Escape Velocity

  1. Consider a spherical asteroid with a radius of 5 km and a mass of 8.65x10^15 kg.
    (a) What is the acceleration of gravity on the surface of this asteroid?
    ANSWER: ___ m/s2
    (b) Suppose the asteroid spins about an axis through its center, like the Earth, with an angular speed . What is the greatest value can have before loose rocks on the asteroid's equator begin to fly off the surface?
    ANSWER: ___ rad/s

    For (a) which I got right.... I used the equation g=(G*M)/R^2
    g=(6.67e-11*8.65e15)/(5000^2)=.023078 m/s2

    For (b) I used the equation Wf^2= Wi^2 + 2*a*d and i substituted the numbers in to get... Wf^2 = 0 + 2(.023037*2pi)(31415.9m*2pi) and I got it to be 95.45 rad/s and for some reason this is not right... am I even using the right equation or is there another equation i can use to get the answer such as maybe... F= (G*M*m)/R^2 ....
     
  2. jcsd
  3. Päällikkö

    Päällikkö 499
    Homework Helper

    I've got no idea what you've done in (b), but have you taken gravity into account at all?

    I'd use centrifugal force.
     
  4. Consider that, in circular motion:

    [tex]a=\frac{v^2}{r}=\omega^2r[/tex]

    If a > g, then what would happen?

    Does this help you?

    Regards,
    Sam
     
  5. so you are saying a =w^2 * r..... so w = sqroot(a/r) so w= sqroot(.023037/5000) = .0021465 ?????
     
  6. already tried that method

    i already tried that method greg and i got the wrong answer...im not liking this topic at all lol:surprised
     
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