Chapter 5, Problem 71GP

** Isabel notices that if she places a small plastic box on a horizontal wooden disk and slowly increases the rotational frequency of the disk, the box flies off the disk at a certain rotational frequency. She investigates this phenomenon by placing the box at different distances d from the edge of the disk and measuring the period of disk revolution T when the box flies off the disk. Her data are presented in the table at right. Based on these data Isabel is able to determine the radius of the disk and the coefficient of static friction between wood and plastic. Explain how she obtains these values and determine them using her data. (Hint: First, write an expression for T in the limiting case when the static friction force is the largest. Then rearrange your equation to obtain a linear dependence on d [this does not necessarily mean that quantity that depends linearly on d is to the first power), draw a graph, plot the best-fit line, and determine the unknown quantities from the information that you obtain from your graph.)

d (m)	T (s)
0.17	0.55
0.16	0.65
0.15	0.72
0.14	0.80
0.13	0.85