The Physics of a Yoyo

Yoyo is a toy that everyone has played at some point in their lives. Yoyo is more than twenty five thousand years old. It is the second oldest toy, after dolls. The yoyo was first documented to be invented in Greece with wood, metal and terra cotta.2 .The disks were decorated with the pictures of their gods. The yoyo moved to the Orient around 1800. The yoyo was used as a weapon in Philippines. Their version was large with sharp edges and spikes attached to a twenty foot long rope for flinging at the enemy or the prey1. The word “yoyo” used in North America was taken after the Philippine language Tagalog, yoyo means “come come” or “come back”. It was a Philippine immigrant named Pedro Flores who brought the yoyo to America. An American man named D.F. Duncan Sr. saw the yoyo manufactured by Pedro Flores and bought the company from him. He mass-produced the new toy with different technologies. It was Duncan who came up with the idea of slip string, consisting of a sliding loop around the axle instead of a knot. The loop allowed the yo-yo to go to ‘sleep’2 which will be discussed later on in the report. Before and after design of a yo-yo.3

A yoyo works by converting potential energy into different kinds of energy as it falls down. When the string is tightly wound around the axle and the yoyo rests in the person’s palm, the yoyo has a lot of potential energy. The potential energy is turned into the two of the following: gravitational energy and the potential to spin as it unwinds. When the yoyo is allowed to fall, the potential energy turns into kinetic energy giving the yoyo linear momentum and angular momentum. Since the yoyo is falling straight towards the ground, this is called the linear momentum. The linear momentum can be calculated using a simple formula p=mv Momentum = mass * velocity. As the spring unwinds, the spool spins which creates angular momentum. Definition of angular momentum is “a quantity associated with how an object moves around a