Speedy the Slipping Yoyo

Compete with friends in this battle-yoyo called as Speedy the slipping Yoyo.

Align all yoyo at the start line. Say 1-2-3 Go! Push your Yoyo on a table or an incline and watch as it bounces back to you on its own. The one which returns first wins!

This is a toy we all used to play with in our childhoods, just take a disk-shape and push it by placing it on the table in a vertical position and then pushing it away while rotating it towards self. In this way, the disc moves forward and then comes back towards the user.

I have used two bottle caps which are metallic in order to prevent easy damage from glass bottles. Also, the bottle caps have a dented circular corners which allow the slipping of the caps on the floor.

The physics behind this concept states that when we push the cap towards the goal, it slips because we have provided a very high speed to the center of the disc, so, it appears that the disc is just moving forcefully horizontally as compared to a car tire which rolls.

When a car tire rolls on a road, the velocity of the center of the disc is equal to the translational speed, therefore, it rolls without slipping, as compared to our toy in which case the speed is provided by our push which slips it as it is greater than the translational speed and when the friction slows the disc, the translational speed is achieved which makes it roll back.

1. Glue - Strong adhesive (to be used with caution and help of friends).
2. Two bottle caps - preferably metallic (as available over the glass bottles).

1. Glue the two bottle caps together such that the flat surface is facing outwards for both the caps.

1. A yoyo without a string, a slipping-rolling disc, a Physics lesson, what more can I say,
2. Enjoy