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View File SimuLAB: Motion in a Circle Interactive simulation lab activity where students explore quantities describing circular motion. Submitter FizziksGuy Submitted 11/30/2017 Category UCM & Gravity  

Name: Walter Lewin Demonstrates Moment of Inertia Category: Rotation Date Added: 2017-12-05 Submitter: FizziksGuy The concept of moment of inertia is demonstrated by rolling a series of cylinders down an inclined plane. Visit physicsworld.com for more videos, webinars and podcasts. http://physicsworld.com/cws/channel/m... Walter Lewin Demonstrates Moment of Inertia

Name: AP Physics 1 - Angular Momentum Category: Rotational Motion Date Added: 2015-11-19 Submitter: FizziksGuy Brief introduction to angular momentum for algebra-based physics courses such as AP Physics 1. AP Physics 1 - Angular Momentum

Name: AP Physics 1: Rotational Kinematics Review Category: Exam Prep Date Added: 23 March 2015 - 09:19 AM Submitter: Flipping Physics Short Description: None Provided Review of the Rotational Kinematics topics covered in the AP Physics 1 curriculum. Content Times: 0:14 Angular Velocity 0:54 Angular Acceleration 1:40 Uniformly Angularly Accelerated Motion 2:34 Uniform Circular Motion 3:30 Tangential Velocity 5:08 Centripetal Force and Centripetal Acceleration 7:10 Conical Pendulum Example Problem 9:36 Period, Frequency and Angular Velocity Multilingual? View Video

The other night I watched the movie Black Hawk Down, which is based on the book of the same name (written by Mark Bowden) which was based on the actual events of the Battle of Mogadishu. The short story is that the US sent Army Rangers, Delta Force operators and pilots from the 160th Special Operations Aviation Regiment to remove Somalian dictator Mohamed Farrah Aidid from power and in October of 1993 they conducted a raid with the intent of capturing two of Aidid's highest advisers. The operation was supposed to take no longer than an hour and incurr no casualties but after a series of complications it became a full battle lasting through the night and into the next morning. The main problem that occurred was that one of the 8 Black Hawk helicopters crashed after losing its tail rotor, which is where physics comes in. Most helicopters have a single horizontal main rotor and a vertical tail rotor. A two rotor system is necessary because the main rotor produces torque in on direction which would cause the helicopter to spin out of control (a notable exception is the NOTAR system which involves a single main rotor and a ducted fan in the tail takes the place of a second rotor). The tail rotor provides a counter torque force (static equilibrium in one axis to move in a straight line) and rotational turning in the x-z plane (other configurations include NOTAR and double main rotor configurations such as 2 coaxial rotors, angled meshed rotors, and front and back or side to side flat rotors). Anyway, in the movie (and real life) the Black Hawks tail rotor is blown off by an RPG causing the pilot to lose control as the craft began to spiral uncontrollably due to unopposed torque and crash. The operation was then updated to include the rescue the crew of the downed helicopter (who all unfortunately died). In the process many Americans were wounded or killed and a second Black Hawk was shot down the same way as the first causing even more problems. Having read the book In the Company of Heros, also by Mark Bowden, which is the true story Michael Durant (the pilot and only survivor of the second crashed helicopter who was taken prisoner and held for 11 days with a broken back and leg) I found the movie to be very close to the actual events and included the shootout in which two delta force snipers sacrificed their lives to protect Durant and a conversation that Durant actually had with one of Aidid's advisers. By the time the battle was over 18 Americans lost their lives with another 80 wounded. A dark day for the American military but a true display of courage on the part of all the soldiers involved.

Torque is the tendency of force to rotate something around an axis. Torque helps you turn a doorknob, it makes a car's tires spin, it basically helps a force act in a circle. Applications of torque equations can help solve real world problems. Locations for supports for bridges can be determined by examining the effects of the torque vehicles would cause on a bridge. An engineer looking to efficiently maximize the potential for producing torque in an engine would choose electrical or diesel power over gasoline power to use the fuel effectively. People who would like to easily compare weights without a scale can easily use torque properties to their advantage, specifically with a balance. Putting a weight at each end of a beam and sliding it over a fulcrum until it balances can help determine relative weights of objects by comparing the lengths of sides of the balance. For example, Person A and Person B are on opposite ends of a log, and the log is balanced. The leg extending to Person A is twice as long as the one extending to Person B. because torque is the length of the arm multiplied by the weight of the object, it can be determined that, because the torques balance, Person B has twice the weight of Person A.