posted by .

A rotating star expands to become a red giant, increasing its average radius from one million km to 100 million km without changing its mass. What happens to the velocity of a piece of this star located at the average radius?

any help would be great THANKS

  • physic -

    Angular momentum has to be conserved.

    angular momentum sphere= 2/5 mr^2 * w

    so if you are increasing r by a factor of 100, then w must decrease by a factor of 10000 to keep angular momentum constant.
    So, velocity at the new average radius is wnew*rnew= 1/10000 * 100= 1/100 of before.

    check my thinking.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. astronomy

    Calculate the escape velocity from a red giant's atmosphere (use the formula for escape velocity from chapter 2). Assume that the star's mass is 1 M and its radius is 100 R How does this compare with the speed at which a planetary …
  2. physics

    Sun will turn into a red giant star one day. Today the sun has a mass of 2*10^30kg and a radius of 70km and an angular velocity of 2.85*10^-6 rad/s. How fast are the particles moving at the surface of the sun?
  3. Physics

    Black Holes are suspected when a visible star is being noticeably pulled by an invisible partner that is more than 3 times as massive as the Sun. A red giant star is accelerated in a linear direction by gravity at 0.075 m/s2 towards …
  4. Astronomy

    How long does it take a protostar with one solar mass to become a main sequence star?
  5. astronomy

    I just wanted to check to make sure I put these in the right order steps of a low mass star a clump forms in a giant molecular cloud. then a prostar forms hydrogen fusion begins the star moves onto the red giant branch, then a helium …

    When some stars use up their fuel, they undergo a catastrophic explosion called a supernova. This explosion blows much or all of a star's mass outward, in the form of a rapidly expanding spherical shell. As a simple model of the supernova …
  7. earth science

    Stellar evolution is the life cycle of a star. A cycle suggests that upon death of a star, another star is born. How is this possible?

    Given the following images, choose the one that most likely represents an O-class star. Star A is a yellow star. Star B is a blue star. Star C is a red star. Star D is a green star. A B C D is it b
  9. Astronomy

    Hi, can you please check my work? I really need to do well on this. 1. What properties of a star are needed to calculate the stars luminosity?
  10. Astronomy

    1. What color are stars that are very hot and very bright?

More Similar Questions