# Galaxies Lab Report

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Intro Galaxies have a variety of shapes that ranges from ellipsoids to spiral galaxies. Spiral galaxies are made up of many individual stars. Moreover, the components of the spiral galaxies move relative to each other. For instance, a rotation curve of a rigid body measures the speed and the radius. However, a rotation curve of a rigid body must have a body where the angular speed is the same. As a result, this lab will help me understand how individual stars move in a galaxy spiral. This lab will also help me understand why the stars speed in the inner part is different from the outer part of the galaxy.

Procedure In the first activity, I determined the circumference and tangential speed of points on spinning DVDs to demonstrate the rotation curve of a rigid body. For instance, the DVD with a radius of 4 has a circumference of 25.13 cm and a tangential speed of 1933.08 cm per second. During the activity, I noticed as the radius increased, the tangential speed also increased. I also noticed the shape of the rigid body rotation curve was linear. Therefore, the linear shape of the rigid body rotation curve demonstrated that the curve was a solid body rotation. In the second activity, I completed the table by determining the speed of the planets in the solar system. The table included the planets, …show more content…

In addition, I realized that the spiral galaxies would not rotate as rigid bodies because the spiral galaxies have different shapes, which illustrates that speed is not proportional to the distance from the center. Moreover, figure 2 illustrates the rotation curve of NGC 3198, which has a flat curve. During the activity, I noticed the rotation curve of NGC 3198 is similar to the rigid body rotator because it measures the angular speed and the radius. As a result, the rotation curve of NGC 3198 illustrates that speed is not proportional to the distance from the