Categorize the motion as periodic or oscillatory motion
(i) Motion of Halley 's comet around the sun
(ii) Motion osf the penedulum of a wall clock
(iii) Motion of liquid n a U-tube when liquid is once compresed in one limb and then left to itself
Hint `:` In oscallatory motion, there is to and fro motion about some mean position.

Explanation

In oscallatory motion, there is to and fro motion about some mean position.