MasteringPhysics8b

MasteringPhysics8b - MasteringPhysics: Assignment Print View

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http://session.masteringphysics.com/myct/assignmentPrint?assignmentI. .. 1 of 13 12/19/2007 2:46 AM [ Print View ] PHCC 141: Physics for Scientists and Engineers I - Fall 2007 8b. Momentum and Impulse Due at 11:59pm on Monday, October 15, 2007 Hide Grading Details Number of answer attempts per question is: 5 You gain credit for: correctly answering a question in a Part, or correctly answering a question in a Hint. You lose credit for: exhausting all attempts or requesting the answer to a question in a Part or Hint, or incorrectly answering a question in a Part. Late submissions: reduce your score by 100% over each day late. Hints are helpful clues or simpler questions that guide you to the answer. Hints are not available for all questions. There is no penalty for leaving questions in Hints unanswered. Grading of Incorrect Answers For Multiple-Choice or True/False questions, you lose 100% / ( # of options - 1 ) credit per incorrect answer. For any other question, you lose 3% credit per incorrect answer. Momentum and Center of Mass Center of Mass and External Forces Learning Goal: Understand that, for many purposes, a system can be treated as a point-like particle with its mass concentrated at the center of mass. A complex system of objects, both point-like and extended ones, can often be treated as a point particle , located at the system's center of mass . Such an approach can greatly simplify problem solving. Before you use the center of mass approach, you should first understand the following terms: System: Any collection of objects that are of interest to you in a particular situation. In many problems, you have a certain freedom in choosing your system. Making a wise choice for the system is often the first step in solving the problem efficiently. Center of mass: The point that represents the "average" position of the entire mass of a system. The postion of the center of mass can be expressed in terms of the position vectors of the particles as . The x coordinate of the center of mass can be expressed in terms of the x coordinates of the particles as . Similarly, the y coordinate of the center of mass can be expressed. Internal force: Any force that results from an interaction between the objects inside your system. As we will show, the internal forces do not affect the motion of the system's center of mass. External force: Any force acting on an object inside your system that results from an interaction with an object outside your system. Consider a system of two blocks that have masses and . Assume that the blocks are point-like particles and are located along the x axis at the coordinates and as shown . In this problem, the blocks can only move along the x axis. Part A
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MasteringPhysics8b - MasteringPhysics: Assignment Print View

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