College Physics
1st Edition
ISBN: 9781938168000
Author: Paul Peter Urone, Roger Hinrichs
Publisher: OpenStax College
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Textbook Question
Chapter 34, Problem 17PE
The core of a star collapses during a supernova, forming a neutron star. 
and it collapses to 10.0 km, find the neutron star’s
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A star with mass m, period Ti = 30 days, and radius ri = 1E4 km collapses into a neutron star with a radius of rf = 3 km. Our goal will be to determine the period Tf of the neutron star. Useful formulae: Li=Lf; L=lw; w=2πf=2π/T; Isphere=2/5mr2
How much angular momentum Li does the star have before it collapses?
Group of answer choices:
A)riTi
B)mr2i
C)mivi
D)Iiwi
What is the rotation rate wi of the star before collapsing?
Group of answer choices
A)riTi
B)mr2i
C)2π/Ti
D)2πfi
Suppose we model the star as a solid sphere of radius ri with moment of inertia 2/5mr2i (a good assumption). What does our description of Li read now?
Group of answer choices
A)2/5mr2i(2πfi)
B)2/5mr2i(2π/Ti)
C)2/5mr2i(mr2i)
D)2/5mr2i(riTi)
How much angular momentum Lf does the star have after it collapses?
Group of answer choices
A)mfvf
B)rfTf
C)I fwf
D)mr2f
What is the rotation rate wf of the star after collapsing?
Group of answer choices
A)2π/Tf…
Consider a pulsar, a collapsed star of extremely high density, with a mass M equal to that of the Sun (1.98 × 1030 kg), a radius R of only 17.4 km, and a rotational period T of 0.0448 s. By what percentage does the free-fall acceleration g differ from the gravitational acceleration ag at the equator of this spherical star?
A star with mass m, period Ti = 30 days, and radius ri = 1E4 km collapses into a neutron star with a radius of rf = 3 km. Our goal will be to determine the period Tf of the neutron star. Useful formulae: Li=Lf; L=lw; w=2πf=2π/?; Isphere=2/5mr2
How much angular momentum Li does the star have before it collapses?
Group of answer choices:
A)riTi
B)mr2i
C)mivi
D)Iiwi
What is the rotation rate ??ωi of the star before collapsing?
Group of answer choices
A)riTi
B)mr2i
C)2π/Ti
D)2πfi
Suppose we model the star as a solid sphere of radius ri with moment of inertia 2/5mr2i (a good assumption). What does our description of Li read now?
Group of answer choices
A)2/5??2i(2πfi)
B)2/5??2i(2π/Ti)
C)2/5??2i(mr2i)
D)2/5??2i(riTi)
How much angular momentum Lf does the star have after it collapses?
Group of answer choices
A)mfvf
B)rfTf
C)I fwf
D)mr2f
What is the rotation rate wf of the star after collapsing?
Group of answer choices
A)2π/Tf…
Chapter 34 Solutions
College Physics
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