When a star collapses it significantly shrinks in size and spins up. Consider a star with a mass of M = 2.2×1030 kg and an initial radius of R; = 6.8×105 km. If the initial period of rotation of the star is T₁ = 28.9 days, find the new rotational period after it collapses to a final radius of Rf = 6.8×10³ km. Treat the star before and after the collapse as a solid sphere with uniform mass distribution (which is not true, of course, but good enough for an estimation). The new rotational period of the star, Tf = Units km Find the ratio between the final and initial rotational kinetic energies of the star. The factor by which the kinetic energy of the star increases, KE₁f/KE₁ = The work done by gravity, W = || X The increase in the rotational kinetic energy of the star comes from gravity. How much work is done by the gravity force while collapsing the star? Units Select an answer Units N
Gravitational force
In nature, every object is attracted by every other object. This phenomenon is called gravity. The force associated with gravity is called gravitational force. The gravitational force is the weakest force that exists in nature. The gravitational force is always attractive.
Acceleration Due to Gravity
In fundamental physics, gravity or gravitational force is the universal attractive force acting between all the matters that exist or exhibit. It is the weakest known force. Therefore no internal changes in an object occurs due to this force. On the other hand, it has control over the trajectories of bodies in the solar system and in the universe due to its vast scope and universal action. The free fall of objects on Earth and the motions of celestial bodies, according to Newton, are both determined by the same force. It was Newton who put forward that the moon is held by a strong attractive force exerted by the Earth which makes it revolve in a straight line. He was sure that this force is similar to the downward force which Earth exerts on all the objects on it.
![When a star collapses it significantly shrinks in size and spins up. Consider a star with a mass of
M = 2.2×1030 kg and an initial radius of R₁ = 6.8×105 km. If the initial period of rotation of the star is
T₁ = 28.9 days, find the new rotational period after it collapses to a final radius of Rf = 6.8×10³ km. Treat
the star before and after the collapse as a solid sphere with uniform mass distribution (which is not true, of
course, but good enough for an estimation).
The new rotational period of the star, Tf =
Find the ratio between the final and initial rotational kinetic energies of the star.
The factor by which the kinetic energy of the star increases, KE₁/KE₁
Units km
=
Units Select an answer ✓
Units N
X
The increase in the rotational kinetic energy of the star comes from gravity. How much work is done by the
gravity force while collapsing the star?
The work done by gravity, W = ||](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F33e6b976-64d5-404f-b3d3-55038b0589a8%2F73c1ce47-981b-43ed-ac3b-7b2fb0c5272a%2Fri3zird_processed.png&w=3840&q=75)
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