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Unformatted text preview: 1 of 7 [ Print View ] Class PH1110A2007 Assignment 7 Due at 5:00pm on Wednesday, September 12, 2007 View Grading Details Atwood Machine Special Cases An Atwood machine consists of two blocks (of masses and ) tied together with a massless rope that passes over a fixed, perfect (massless and frictionless) pulley. In this problem you'll investigate some special cases where physical variables describing the Atwood machine take on limiting values. Often, examining special cases will simplify a problem, so that the solution may be found from inspection or from the results of a problem you've already seen. For all parts of this problem, take upward to be the positive direction and take the gravitational constant, , to be positive. Part A Consider the case where and are both nonzero, and . Let be the magnitude of the tension in the rope connected to the block of mass , and let be the magnitude of the tension in the rope connected to the block of mass . Which of the following statements is true? ANSWER: is always equal to . is greater than by an amount independent of velocity. is greater than but the difference decreases as the blocks increase in velocity. There is not enough information to determine the relationship between and . Part B Now, consider the special case where the block of mass is not present. Find the magnitude, , of the tension in the rope. Try to do this without equations; instead, think about the physical consequences. Hint B.1 How to approach the problem Hint not displayed Hint B.2 Which physical law to use Hint not displayed ANSWER: = 0 Part C For the same special case (the block of mass not present), what is the acceleration of the block of mass ? Express your answer in terms of , and remember that an upward acceleration should be positive. 2 of 7 ANSWER: = Part D Next, consider the special case where only the block of mass is present. Find the magnitude, , of the tension in the rope. ANSWER: = 0 Part E For the same special case (the block of mass not present) what is the acceleration of the end of the rope where the block of mass would have been attached?...
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 Fall '08
 Kiel
 Acceleration, Force, Friction, Mass

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