A Disk Is Suspended by a Nail Such That It

Multiple Choice

A disk is suspended by a nail such that it pivots in a vertical plane about a point on the edge of the disk. If the period of oscillation of the disk is 1.25 s, what is the disk's radius?

A) 26 cm
B) 78 cm
C) Cannot answer without knowing the disk's mass
D) 51 cm