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

To categorize the given motions as periodic or oscillatory, we need to understand the definitions of both terms:

1. **Periodic Motion**: This is a type of motion where an object repeats its path after a fixed interval of time. The motion does not necessarily have to be about a mean position.

2. **Oscillatory Motion**: This is a specific type of periodic motion where an object moves back and forth around a central or mean position.

Now, let's analyze each statement one by one:

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