College Physics
OER 2016 Edition
ISBN: 9781947172173
Author: OpenStax
Publisher: OpenStax College
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Chapter 34, Problem 25PE
Construct Your Own Problem
Consider a supermassive black hole near the center of a galaxy. Calculate the radius of such an object based on its mass. You must consider how much mass is reasonable for these large objects, and which is now nearly directly observed. (Information on black holes posted on the Web by NASA and other agencies is reliable, for example.)
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for 14 i observed the galaxy end aroung 5 kpc.
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Chapter 34 Solutions
College Physics
Ch. 34 - Explain why it only appears that we are at the...Ch. 34 - If there is no observable edge to the universe,...Ch. 34 - If the universe is infinite, does it have a...Ch. 34 - Another known cause of red shift in light is the...Ch. 34 - If some unknown cause of red shiftsuch as light...Ch. 34 - Olbers’s paradox poses an interesting question: If...Ch. 34 - If the cosmic microwave background radiation...Ch. 34 - The decay of one type of Kmeson is cited as...Ch. 34 - Distances to local galaxies are determined by...Ch. 34 - Distances to very remote galaxies are estimated...
Ch. 34 - If the smallest meaningful time interval is...Ch. 34 - Quantum gravity, if developed, would be an...Ch. 34 - Does observed gravitational lensing correspond to...Ch. 34 - Suppose you measure the red shifts of all the...Ch. 34 - What are gravitational waves, and have they yet...Ch. 34 - Is the event horizon of a black hole the actual...Ch. 34 - Suppose black holes radiate their mass away and...Ch. 34 - Discuss the possibility that star velocities at...Ch. 34 - How does relativistic time dilation prohibit...Ch. 34 - If neutrino oscillations do occur, will they...Ch. 34 - Lacking direct evidence of WIMPs as dark matter,...Ch. 34 - Must a complex system be adaptive to be of...Ch. 34 - State a necessary condition for a System to be...Ch. 34 - What is critical temperature Tc? Do all materials...Ch. 34 - Explain how good thermal contact with liquid...Ch. 34 - Not only is liquid nitrogen a cheaper coolant than...Ch. 34 - For experimental evidence particularly of...Ch. 34 - Discuss whether you think there are limits to what...Ch. 34 - Find the approximate mass of the luminous matter...Ch. 34 - Find the approximate mass of the dark and luminous...Ch. 34 - (a) Estimate the mass of the luminous matter in...Ch. 34 - If a galaxy is 500 Mly away from us, how fast do...Ch. 34 - On average, how far away are galaxies mat are...Ch. 34 - Our solar system orbits the center of the Milky...Ch. 34 - (a) What is the approximate speed relative to us...Ch. 34 - (a) Calculate The approximate age of the universe...Ch. 34 - Assuming a circular orbit for the Sun about the...Ch. 34 - (a) What is the approximate force of gravity on a...Ch. 34 - Andromeda galaxy is the closest large galaxy and...Ch. 34 - (a) A particle and its antiparticle are at rest...Ch. 34 - The average particle energy needed to observe...Ch. 34 - The peak intensity of the CMBR occurs at a...Ch. 34 - (a) What Hubble constant corresponds to an...Ch. 34 - Show that the velocity of a star orbiting its...Ch. 34 - The core of a star collapses during a supernova,...Ch. 34 - Using data from the previous problem, find the...Ch. 34 - Distances to the nearest stars (up to 500 by away)...Ch. 34 - (a) Use the Heisenberg uncertainty principle to...Ch. 34 - Construct Your Own Problem Consider a star moving...Ch. 34 - What is the Schwarzschild radius of a blank hole...Ch. 34 - Black holes with masses smaller than muse formed...Ch. 34 - Supermassive black holes are thought to exist at...Ch. 34 - Construct Your Own Problem Consider a supermassive...Ch. 34 - The characteristic length of entities in...Ch. 34 - If the dark matter in the Milky Way were composed...Ch. 34 - The critical mass density needed to just halt the...Ch. 34 - Assume the average density of the universe is 0.1...Ch. 34 - To get an idea of how empty deep spam is on the...Ch. 34 - A section of superconducting wire carries a...
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- Once again in this chapter, we see the use of Kepler’s third law to estimate the mass of supermassive black holes. In the case of NGC 4261, this chapter supplied the result of the calculation of the mass of the black hole in NGC 4261. In order to get this answer, astronomers had to measure the velocity of particles in the ring of dust and gas that surrounds the black hole. How high were these velocities? Turn Kepler’s third law around and use the information given in this chapter about the galaxy NGC 4261-the mass of the black hole at its center and the diameter of the surrounding ring of dust and gas-to calculate how long it would take a dust particle in the ring to complete a single orbit around the black hole. Assume that the only force acting on the dust particle is the gravitational force exerted by the black hole. Calculate the velocity of the dust particle in km/s.arrow_forwardThe first clue that the Galaxy contains a lot of dark matter was the observation that the orbital velocities of stars did not decreases with increasing distance from the center of the Galaxy. Construct a rotation curve for the solar system by using the orbital velocities of the planets, which can be found in Appendix F. How does this curve differ from the rotation curve for the Galaxy? What does it tell you about where most of the mass in the solar system is concentrated?arrow_forwardThe next step in deciding whether the object in Exercise 25.25 is a black hole is to estimate the density of this mass. Assume that all of the mass is spread uniformly throughout a sphere with a radius of 20 lighthours. What is the density in kg/km3? (Remember that the volume of a sphere is given by V=43R3 .) Explain why the density might be even higher than the value you have calculated. How does this density compare with that of the Sun or other objects we have talked about in this book?arrow_forward
- What is the orbital period of a bit of matter in an accretion disk that is located 4 ✕ 105 km from a 87 M black hole? Use the circular orbit velocity formula.arrow_forwardDistances to very remote galaxies are estimated based on their apparent type, which indicate the number of stars in thegalaxy, and their measured brightness. Explain how the measured brightness would vary with distance. Would there be anycorrection necessary to compensate for the red shift of the galaxy (all distant galaxies have significant red shifts)? Discusspossible causes of uncertainties in these measurementsarrow_forwardWhat is the Schwarzschild radius (in km) of a 6Msun black hole? What fraction of the Earth's radius is this? What percent of the speed of light (2.998 x 108 m/s) is the escape velocity at the Schwarzschild radius? Part 1 of 3 The Schwarzschild radius of a black hole is given by: 2GM Rs = c2 so for the given mass, 2G(6)(Msun) Rs c2 where M. Sun = 1.99 x 1030 kg. Then convert this into kilometers using 1 km = 1,000 m. Rs kmarrow_forward
- 6arrow_forwardDistribution of Dark matter The most mass of our Milky Way is contained in an inner region close to the core with radius R0.Because the mass outside this inner region is almost constant, the density distribution can bewritten as following (assume a flat Milky Way with height z0):ρ(r) = (ρ0, r ≤ R00, r > R0(a) Derive an expression for the mass M(r) enclosed within the radius r.(b) Derive the expected rotational velocity of the Milky Way v(r) at a radius r.arrow_forward(Astronomy) PSR1913+16 Problem III. As the shape of the graph shown is not skewed, the orbit can be assumed circular. Also assume the system is viewed edge-on (that is, the orbital system is not inclined to the observer). Using these assumptions, the maximum radial velocities, and the orbital period T = 7.75 hours, find the orbital radii of the stars from the center of mass. (Hints: The figures below may be helpful. Use v = 2πr/P, where v is velocity, P is period, and r is radius. Note: redshifts have positive radial velocities values in the upper figure, whereas blueshifts have negative radial velocity values.)arrow_forward
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