A 20-ft ladder weighing 70 lb (assumed concentrated at its mid-length) rests on a vertical plane with its lower end on a horizontal floor and its upper end against a vertical wall. The ladder supports a 180-lb person at the top (upper end). The coeffic ient of static friction at the floor is 0.25 and at the wall is also 0.25. (Note: wall and floor have frictional resistance. Example in book will help. The example is the one I uploaded in the 'Book Misprint' folder. Note that the location of the 180-lb person in this homework problem is at the very top of the ladder- not at D). a) Determine the smallest angle that the ladder can make with the floor before slipping begins. b) Determine the frictional force fbetween the floor and the lower end of the ladder.

A 20-ft ladder weighing 70 lb (assumed concentrated at its mid-length) rests on a vertical plane with its lower end on a horizontal floor and its upper end against a vertical wall. The ladder supports a 180-lb person at the top (upper end). The coeffic ient of static friction at the floor is 0.25 and at the wall is also 0.25. (Note: wall and floor have frictional resistance. Example in book will help. The example is the one I uploaded in the 'Book Misprint' folder. Note that the location of the 180-lb person in this homework problem is at the very top of the ladder- not at D). a) Determine the smallest angle that the ladder can make with the floor before slipping begins. b) Determine the frictional force fbetween the floor and the lower end of the ladder.

International Edition---engineering Mechanics: Statics, 4th Edition

4th Edition

ISBN:9781305501607

Author:Andrew Pytel And Jaan Kiusalaas

Publisher:Andrew Pytel And Jaan Kiusalaas

Chapter7: Dry Friction

Section: Chapter Questions

Problem 7.3P: Two identical chairs, each weighing 14 lb, are stacked as shown. The center of gravity of each chair...

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