Suspended shelf


Dave needed more storage for his school
books and clothes, but he did not want to use any floor space. He thought
that a hanging shelf would solve the problem to store 6 book
boxes and 6 clothes boxes, weighing 45 lb and 20 lb per box, respectively.
To save money, he decided to use wood for both the shelf and the
hanging rods.
What is known:
 Each box is 1foot square on its base.
 The shelf board weigts 35 lbs.
 The rod material is Douglas Fir.
 Rods are assumed to be circular.
 To be safe, a factor of safety of 4 is applied.
 Wood rods are available in increments of 1/16".
 There are a total of 4 rods.
