Задача id13302

At the bottom of a small sealed test tube, suspended above the table on a thread, sits a fly whose mass is equal to the mass of the test tube, and the distance from the bottom to the surface of the table is equal to the length of the test tube l. The thread is burned out, and during the fall the fly flies from the bottom to the very top end of the test tube. Determine the time after which the lower end of the test tube hits the table.

Answer. Format gif