OpenStax College Physics for AP® Courses, Chapter 16, Problem 22 (Problems & Exercises)

This is College Physics Answers with Shaun Dychko. We are told that a simple pendulum has a period of 0.500 seconds and we are asked to find what length it must have? Well the formula for the period is 2π times the square root of its length divided by the acceleration due to gravity so we solve this for L. So we'll square both sides and we get period squared equals 4π squared times L over g and then multiply both sides by g over 4π squared. Then we get L is T squared times g divided by 4π squared. So that's 0.500 seconds squared times 9.80 meters per second squared divided by 4π squared which is 0.06206 meters which is 6.21 centimeters.