The ear-ring of a lady shown in figure (12-E18) has a 3 cm long light suspension wire (a) Find the time period of small oscillations if the lady is standing on the ground. (b) The lady now sits in a merry-go-round moving at 4 m s-1 in a circle of radius 2 m. Find the time period of small oscillations of the ear-ring.
(a) 0.34 s
(b) 0.30 s
Sol: (a) given length l= 3cm=0.03m
Time period 
=
=0.3476 sec
(b) Now, lady is in circular motion on merry-go-round of radius r=2m. A centripetal force also acts on the earring now. Which is 
the resultant acceleration on the ear-ring will be
=
= 0.30 sec.
1