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- https://phys.libretexts.org/Bookshelves/Astronomy__Cosmology/Astronomy_1e_(OpenStax)/25%3A_The_Milky_Way_Galaxy/25.01%3A_The_Architecture_of_the_GalaxyThe Milky Way Galaxy consists of a thin disk containing dust, gas, and young and old stars; a spherical halo containing populations of very old stars, and globular star clusters; a thick, more diffuse...The Milky Way Galaxy consists of a thin disk containing dust, gas, and young and old stars; a spherical halo containing populations of very old stars, and globular star clusters; a thick, more diffuse disk with stars that have properties intermediate between those in the thin disk and the halo; a peanut-shaped nuclear bulge of mostly old stars around the center; and a supermassive black hole at the very center. The Sun is located roughly halfway out of the Milky Way.
- https://phys.libretexts.org/Bookshelves/Astronomy__Cosmology/Astronomy_1e_(OpenStax)/21%3A_The_Birth_of_Stars_and_the_Discovery_of_Planets_outside_the_Solar_SystemDo planets orbit other stars or is ours the only planetary system? In the past few decades, new technology has enabled us to answer that question by revealing nearly 3500 exoplanets in over 2600 plane...Do planets orbit other stars or is ours the only planetary system? In the past few decades, new technology has enabled us to answer that question by revealing nearly 3500 exoplanets in over 2600 planetary systems. Even before planets were detected, astronomers had predicted that planetary systems were likely to be byproducts of the star-formation process. In this chapter, we look at how interstellar matter is transformed into stars and planets.
- https://phys.libretexts.org/Courses/Joliet_Junior_College/Physics_201_-_Fall_2019v2/Book%3A_Custom_Physics_textbook_for_JJC/09%3A_Linear_Momentum_and_Collisions/9.06%3A_Conservation_of_Linear_Momentum_(Part_2)If we define a system that consists of both Philae and Comet 67/P, then there is no net external force on this system, and thus the momentum of this system is conserved. (We’ll neglect the gravitation...If we define a system that consists of both Philae and Comet 67/P, then there is no net external force on this system, and thus the momentum of this system is conserved. (We’ll neglect the gravitational force of the sun.) Thus, if we calculate the change of momentum of the lander, we automatically have the change of momentum of the comet.
- https://phys.libretexts.org/Courses/Joliet_Junior_College/Physics_201_-_Fall_2019v2/Book%3A_Custom_Physics_textbook_for_JJC/12%3A_Temperature_and_Kinetic_Theory/12.06%3A_The_Kinetic_Theory_of_GasesGases are literally all around us—the air that we breathe is a mixture of gases. Other gases include those that make breads and cakes soft, those that make drinks fizzy, and those that burn to heat ma...Gases are literally all around us—the air that we breathe is a mixture of gases. Other gases include those that make breads and cakes soft, those that make drinks fizzy, and those that burn to heat many homes. Engines and refrigerators depend on the behaviors of gases, as we will see in later chapters. As we discussed in the preceding chapter, the study of heat and temperature is part of an area of physics known as thermodynamics.
- https://phys.libretexts.org/Courses/Joliet_Junior_College/Physics_201_-_Fall_2019/Book%3A_Physics_(Boundless)/03%3A_VectorsVectors are essential to physics and engineering. Many fundamental physical quantities are vectors, including displacement, velocity, force, and electric and magnetic vector fields. Scalar products of...Vectors are essential to physics and engineering. Many fundamental physical quantities are vectors, including displacement, velocity, force, and electric and magnetic vector fields. Scalar products of vectors define other fundamental scalar physical quantities, such as energy. Vector products of vectors define still other fundamental vector physical quantities, such as torque and angular momentum.
- https://phys.libretexts.org/Courses/Joliet_Junior_College/Physics_201_-_Fall_2019v2/Book%3A_Custom_Physics_textbook_for_JJC/14%3A_Thermodynamics/14.20%3A_The_Second_Law_of_Thermodynamics_(Exercise)For the entire cycle, calculate (a) the work done by the gas, (b) the heat into or out of the gas, (c) the change in the internal energy of the gas, and (d) the change in entropy of the gas.
- https://phys.libretexts.org/Courses/Joliet_Junior_College/Physics_201_-_Fall_2019/Book%3A_Physics_(Boundless)/13%3A_Thermodynamics/13.1%3A_The_First_Law_of_Thermodynamics/The_First_Law_of_Thermodynamics_(Answer)So that the process is represented by the curve \(\displaystyle p=nRT/V\) on the pV plot for the evaluation of work. In this example, water contracts upon heating, so if we add heat at constant pressu...So that the process is represented by the curve \(\displaystyle p=nRT/V\) on the pV plot for the evaluation of work. In this example, water contracts upon heating, so if we add heat at constant pressure, work is done on the water by surroundings and therefore, \(\displaystyle C_p\) is less than \(\displaystyle C_V\). the sum of parts (a) and (b); d. \(\displaystyle T_1=\frac{p_1V_1}{nR}\) and \(\displaystyle T_2=\frac{p_2V_2}{nR}\)
- https://phys.libretexts.org/Courses/Joliet_Junior_College/Physics_201_-_Fall_2019/Book%3A_Physics_(Boundless)/07%3A_Work_and_Energy/7.15%3A_Conservative_and_Non-Conservative_ForcesA conservative force is one for which the work done is independent of path. Equivalently, a force is conservative if the work done over any closed path is zero. A non-conservative force is one for whi...A conservative force is one for which the work done is independent of path. Equivalently, a force is conservative if the work done over any closed path is zero. A non-conservative force is one for which the work done depends on the path. The component of a conservative force, in a particular direction, equals the negative of the derivative of the potential energy for that force, with respect to a displacement in that direction.
- https://phys.libretexts.org/Bookshelves/Astronomy__Cosmology/Astronomy_1e_(OpenStax)/05%3A_Radiation_and_Spectra/5.06%3A_The_Doppler_EffectIf an atom is moving toward us when an electron changes orbits and produces a spectral line, we see that line shifted slightly toward the blue of its normal wavelength in a spectrum. If the atom is mo...If an atom is moving toward us when an electron changes orbits and produces a spectral line, we see that line shifted slightly toward the blue of its normal wavelength in a spectrum. If the atom is moving away, we see the line shifted toward the red. This shift is known as the Doppler effect and can be used to measure the radial velocities of distant objects.
- https://phys.libretexts.org/Courses/Joliet_Junior_College/Physics_201_-_Fall_2019v2/Book%3A_Custom_Physics_textbook_for_JJC/03%3A_Vectors/3.09%3A_Products_of_Vectors_(Part_2)Another kind of vector multiplication is the vector product, also known as the cross product, which results in a vector perpendicular to both of the factors. The vector product has the distributive pr...Another kind of vector multiplication is the vector product, also known as the cross product, which results in a vector perpendicular to both of the factors. The vector product has the distributive property and the anticommutative property, and is obtained by multiplying the magnitudes of the two vectors by the sine of the angle between them. The direction of the vector product can be determined by the corkscrew right-hand rule.
- https://phys.libretexts.org/Courses/Tuskegee_University/Algebra_Based_Physics_I/02%3A_One-Dimensional_Kinematics/2.05%3A_AccelerationAcceleration is the rate at which velocity changes. In symbols, average acceleration a− is a−= ΔvΔt=vf−v0tf−t0. The SI unit for acceleration is m/s2 . Acceleration is a vector, and thus has a both...Acceleration is the rate at which velocity changes. In symbols, average acceleration a− is a−= ΔvΔt=vf−v0tf−t0. The SI unit for acceleration is m/s2 . Acceleration is a vector, and thus has a both a magnitude and direction. Acceleration can be caused by either a change in the magnitude or the direction of the velocity. Instantaneous acceleration a is the acceleration at a specific instant in time. Deceleration is an acceleration with a direction opposite to that of the velocity.
