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Unformatted text preview: PHYS171 Exam 3 practice Fall 2011 Name: _____________________ Student ID #: ________ 1 Short Answer Questions 1) You need to launch an object at sufficient velocity so that it entirely escapes the earths gravitation field (i.e., at escape velocity). To minimize the energy required it is better to (a) launch from the highest mountain accessible (b) launch from the deepest valley accessible (c) it doesnt matter, why? (5 points) 2) You have a slingshot that launches an object at a fixed velocity. Standing on the roof of this building, you must use it to launch your iPhone so that it lands on the ground below, at which point you can assume it comes instantly to rest. To minimize the risk of damage, should you (a) launch it straight up (b) launch it straight down (c) launch it horizontally (d) it does not matter. Why? (5 points) 3) A baseball bat is 1 meter long, and weighs 0.75 kg. What is the effective moment of intertia when a baseball player swings the bat (10 points)? 4) One cylinder rolls down an inclined plane without slipping and a second identical cylinder slides down the same inclined plane without friction. Which cylinders center of mass is moving faster when it reaches the bottom of the inclined plane. (a) rolling of (b) sliding. (5 points) PHYS171 Exam 3 practice...
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