physics
posted by melissa .
How many uniform, identical textbooks of width 25.0 cm can be stacked on top of each other on a level surface without the stack falling over if each successive book is displaced 3.00 cm in width relative to the book below it?
If the books are 5.00 cm thick, what will be the height of the center of mass of the stack above the level surface?

okay

divide width by displacement and add the 1st book.
25/3 = 8.33333 + 1 = 9 books
take the number of books form the 1st answer and multiply by the thickness of the books and then divide by 2. 9*5 = 45/2 = 22.5 
divide width by displacement and add the 1st book.
25/3 = 8.33333 + 1 = 9 books
take the number of books form the 1st answer and multiply by the thickness of the books and then divide by 2. 9*5 = 45/2 = 22.5