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Unformatted text preview: P1112 Spring 2009 Homework #5, due second section of the week of Feb. 16. Solutions will be posted Feb. 20. Quiz on HW#5 first section meeting of week of Feb. 23. Reading: Text Chapter 5.1 5.3, 12.1, 12.2. Not all concepts will be covered in class you are responsible for all material in the assigned reading and in the homework problems. Problems: 1. An athlete whose mass is 90.0 kg is performing weight-lifting exercises. Starting from the rest position he lifts, with constant acceleration, a barbell that weighs 490 N. He lifts the barbell a distance of 0.60 m in 1.6 s. (a) Draw a clearly labeled free-body diagram for the barbell and for the athlete. (b) Use the diagrams in part a) and Newtons laws to find the total force that his feet exert on the ground as he lifts the barbell. 2. A box whose weight is w is pulled at constant speed along a level floor by a force F that is directed at an angle above horizontal. The coefficient of kinetic friction between the floor and box is k . (a) In terms of , k , and w , calculate the required force F ....
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