A star has initially a radius of 640000000 m and a period of rotation about its axis of 20 days. Eventually it changes into a neutron star with a radius of only 50000 m and a period of 0.2 s. Assuming that the mass has not changed, find Assume a star has the shape of a sphere. (Suggestion: do it with formula first, then put the numbers in) [Recommended time : 5-8 minutes] (a) the ratio of initial to final angular momentum (Li/Lf) Oa. 1.42E+15 Ob. 19 Oc. 0.0527 Od. 7.06E-16 (b) the ratio of initial to final kinetic energy Oa. 8.18E-23 Ob. 456000 Oc. 2.19E-6 Od. 1.22E+22

A star has initially a radius of 640000000 m and a period of rotation about its axis of 20 days. Eventually it changes into a neutron star with a radius of only 50000 m and a period of 0.2 s. Assuming that the mass has not changed, find Assume a star has the shape of a sphere. (Suggestion: do it with formula first, then put the numbers in) [Recommended time : 5-8 minutes] (a) the ratio of initial to final angular momentum (Li/Lf) Oa. 1.42E+15 Ob. 19 Oc. 0.0527 Od. 7.06E-16 (b) the ratio of initial to final kinetic energy Oa. 8.18E-23 Ob. 456000 Oc. 2.19E-6 Od. 1.22E+22

College Physics

11th Edition

ISBN:9781305952300

Author:Raymond A. Serway, Chris Vuille

Publisher:Raymond A. Serway, Chris Vuille

Chapter1: Units, Trigonometry. And Vectors

Section: Chapter Questions

Problem 1CQ: Estimate the order of magnitude of the length, in meters, of each of the following; (a) a mouse, (b)...

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Concept explainers

Stellar evolution

We may see thousands of stars in the dark sky. Our universe consists of billions of stars. Stars may appear tiny to us but they are huge balls of gasses. Sun is a star of average size. Some stars are even a thousand times larger than the sun. The stars do not exist forever they have a certain lifetime. The life span of the sun is about 10 billion years. The star undergoes various changes during its lifetime, this process is called stellar evolution. The structure of the sun-like star is shown below.

Red Shift

It is an astronomical phenomenon. In this phenomenon, increase in wavelength with corresponding decrease in photon energy and frequency of radiation of light. It is the displacement of spectrum of any kind of astronomical object to the longer wavelengths (red) side.

Question

100%

A star has initially a radius of 640000000 m and a period of rotation about its axis of
20 days. Eventually it changes into a neutron star with a radius of only 50000 m
and a period of 0.2 s. Assuming that the mass has not changed, find
Assume a star has the shape of a sphere.
(Suggestion: do it with formula first, then put the numbers in)
[Recommended time : 5-8 minutes]
(a) the ratio of initial to final angular momentum (Li/Lf)
Oa. 1.42E+15
Ob. 19
Oc. 0.0527
Od. 7.06E-16
(b) the ratio of initial to final kinetic energy
Oa. 8.18E-23
Ob. 456000
Oc. 2.19E-6
Od. 1.22E+22
52%

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