What is second's pendulum ? Find the length of second's pendulum for `g = 9.8 m//s^(2)` ? Also write expressions for the time period if the second's pendulum is an a carriage which is accelerating (a) upwards (b) downwards (c ) horizontally. Also, fin the value of time period of it if is made to oscillate a freely falling lift.

Explanation

### Step-by-Step Solution:

1. **Definition of Second's Pendulum**:
A second's pendulum is defined as a simple pendulum that has a time period of exactly 2 seconds.

2. **Finding the Length of the Second's Pendulum**:
The formula for the time period \( T \) of a simple pendulum is given by:
\[
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