ベルヌーイの定理、力学 https://www.youtube.com/watch?v=6APNDuW5WaM https://www.youtube.com/watch?v=oMOpfBVJD1Y&list=PLZxjsvw39Ev5tPvVR3DirBJ2Xpr4MaMc2&index=1
断面二次モーメント https://www.youtube.com/watch?v=8Ra5RmJFaLE https://www.youtube.com/watch?v=WC6n-whoPPg https://www.youtube.com/watch?v=FY8kf3zfGKo