Question

What is the length of a simple pendulum which ticks second?

Answer 1

A simple pendulum which ticks seconds is a second pendulum. Its time period `T=2s.` If l is the length of this pendulum, then
`T=2pisqrt(l)/(g)`
or `l=(gT^(2))/(4pi^(2))=(9.8xx2^(2))/(4xx(22//7)^(2))=0.99m`