Angular Momentum

概要

Source: Nicholas Timmons, Asantha Cooray, PhD, Department of Physics & Astronomy, School of Physical Sciences, University of California, Irvine, CA

Angular momentum is defined as the product of the moment of inertia and the angular velocity of the object. Like its linear analog, angular momentum is conserved, meaning that the total angular momentum of a system will not change if there are no external torques on the system. A torque is the rotational equivalent of a force. Because it is a conserved, angular momentum is an important quantity in physics.

The goal of this experiment is to measure the angular momentum of a rotating rod and to use the conservation of angular momentum to explain two rotational demonstrations.

手順

1. Test the theory of the conservation of angular momentum with the bike wheel.

While sitting in a chair that can freely rotate, start spinning the bike wheel and then hold it by the handles so that its direction of angular momentum is vertical.
While holding the wheel by the two handles, flip the wheel over so that its angular momentum points in the opposite direction. Notice how the chair will begin to rotate.

2. Test the theory of the conservation of angular momen

結果

Mass (g)	Angular momentum at halfway (kg m²)/s	Angular momentum at bottom (kg m²)/s	Difference (kg m²)/s
200	0.41	0.58	0.17
500	0.66	0.91	0.25
1,000	0.93	Log in or to access full content. Learn more about your institution’s access to JoVE content here 申請書と概要 Just like in the spinning chair portion of the lab, changing the moment of inertia of an object can increase or decrease the angular velocity of that object. Figure skaters take advantage of this and will sometimes begin spinning with their arms outstretched and then bring their arms in close to their bodies, which will make them spin much faster. Why is it easier to balance on a bike when it is in motion? The answer is angular momentum. When the wheels are not spinning, it is easy for Log in or to access full content. Learn more about your institution’s access to JoVE content here タグ Angular Momentum Conservation Of Angular Momentum Rotational Dynamics Linear Momentum Net External Force Net External Torque Spinning Mass Rotational Motion Radius Translational Momentum Tangential Velocity Angular Velocity Right hand Rule 1. Test the theory of the conservation of angular momentum with the bike wheel. While sitting in a chair that can freely rotate, start spinning the bike wheel and then hold it by the handles so that its direction of angular momentum is vertical. While holding the wheel by the two handles, flip the wheel over so that its angular momentum points in the opposite direction. Notice how the chair will begin to rotate. 2. Test the theory of the conservation of angular momentum with two weights. While sitting in a chair that can freely rotate, hold two weights out at arm's length. Have a partner get the chair spinning and then bring the weights in close to the chest. Notice the increased speed of rotation of the chair. 3. Measure the change of angular momentum in the spinning rod. Measure the length of the rod and its mass. Using a meter stick, measure the halfway point of the falling weight and mark the vertical beam with tape in order to have a reference. Calculate the moment of inertia of the rod. Add 200 g to the end of the string and wind it up to the top. Take notice of where the halfway point of the string is located. Release the weight and measure the amount of time it takes to get to the halfway mark and then again to the bottom. Do this three times and take the average values. Calculate the angular momentum at both points. Increase the weight at the end of the string to 500 g and repeat step 3.3. Increase the weight to 1,000 g and repeat step 3.3. スキップ先... 0:03 Overview 0:57 Principle of Angular Momentum Conservation 2:17 Demonstration of Angular Momentum Conservation 4:32 Measurement of Angular Momentum for a Spinning Rod 6:21 Data Analysis and Results 7:54 Applications 9:01 Summary このコレクションのビデオ: Now Playing Angular Momentum Physics I 36.2K 閲覧数 Newton's Laws of Motion Physics I 75.7K 閲覧数 Force and Acceleration Physics I 79.0K 閲覧数 Vectors in Multiple Directions Physics I 182.3K 閲覧数 Kinematics and Projectile Motion Physics I 72.5K 閲覧数 Newton's Law of Universal Gravitation Physics I 190.7K 閲覧数 Conservation of Momentum Physics I 43.3K 閲覧数 Friction Physics I 52.8K 閲覧数 Hooke's Law and Simple Harmonic Motion Physics I 61.3K 閲覧数 Equilibrium and Free-body Diagrams Physics I 37.3K 閲覧数 Torque Physics I 24.3K 閲覧数 Rotational Inertia Physics I 43.5K 閲覧数 Energy and Work Physics I 49.7K 閲覧数 Enthalpy Physics I 60.4K 閲覧数 Entropy Physics I 17.6K 閲覧数個人情報保護方針利用規約一般データ保護規則お問い合わせ図書館への推薦 JoVE ニュースレター研究 JoVE Journal メソッドコレクション JoVE Encyclopedia of Experiments アーカイブ教育 JoVE Core JoVE Science Education JoVE Lab Manual JoVE Business JoVE Quiz JoVE Playlist 教員用サイト著者概要出版プロセス編集委員会スコープと指針査読よくある質問お申し込み図書館員概要お客様の声定期購読アクセスリソース図書館諮問委員会よくある質問 JoVEについて概要経営陣ブログ JoVE Help Center JoVE Sitemap Copyright © 2023 MyJoVE Corporation. All rights reserved