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Unformatted text preview: Physics 3221 Mechanics I Fall Term 2010 Quiz 2 This is a 20 min. quiz (closed book). There is only one problem. Problem 1. [5 pts] You are standing next to a building and want to toss your cell phone to your friend who is leaning out of a thirdfloor window which is a distance h above the ground. Assume that the air drag is proportional to the square of the velocity, i.e. F r  vector F r  = mkv 2 . (a) Find the minimum velocity v min with which you must throw the cell phone vertically up so that it can reach your friend. Express your answer in terms of h , k and g . (b) Check the validity of your answer from part (a) by discussing the following limits: k 0, g 0, h 0, k , g , h . Solution. (a) Choosing the z axis pointing up, Newtons law reads m z = mg mk z 2 (the particle is moving up hence the friction force acts downwards). The problem only involves the velocity v and position z , thus time is not relevant to this problem and it is convenient to...
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This note was uploaded on 12/15/2011 for the course PHY 3221 taught by Professor Chan during the Spring '08 term at University of Florida.
 Spring '08
 CHAN
 mechanics

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