Added the algorithm to compute the time period of a simple pendulum (#10265)

* Added the algorithm to compute the time period of a simple pendulum

* imported g form scipy and changed doctests accordingly

* fixed formatting

* applied all suggested changes from code review

* Apply suggestions from code review

* [pre-commit.ci] auto fixes from pre-commit.com hooks

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Co-authored-by: Tianyi Zheng <tianyizheng02@gmail.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>