In the video we reach a conclusion. We have energy accumulated and to keep the system turning we need about 1J of energy each second to keep it turning.

**#120**- 12 Jun 2016
- 3:29

How much power can we accumulate? - if we have 6 systems like this rotating then we could power 1 lightbulb for about a second.

Find more about rubber bands and flywheels in the videos from the following playlist:

### Rubber band attachment with a flywheel - solving FLL 2014 Search Engine

### English

In this video I would like to reach a cnclusion. The long waited conclusion with this system.

As we saw in the previous videos we have energy accumulated which was about 5 joules and in order to keep this system rotating. This system of 3 wheels that are acting like fly wheels. We need to add one additional joule of energy each second. In order to keep them rotating. So, as we start the system, we need more energy in order to reach the maximum speed of rotation of these wheels and then we add 1 joule for each second and we can see now what's the relation. We have 5 joules here in order to keep them each second we must add 1 joule from the motor. If we disconnect the motor, the it would take us about 5 seconds for the whole system to stop and why because we are loosing energy in this system. As you can see there is a system of gears. There are some axles, there are some frictions. And each second these losses in the systems are 1 joule. Now what exactly is a joule if we have 30 joules, imagine that we have 6 systems like this, about 18 wheels and if we stack them together and if we turn them and rotate them to the maximum speed, then we can power a light bulb for about a second, a small light bulb, like 30 W. This is exactly what 30 joules are. Here we have about 5 joules. So, we need about 18 such wheels so 6 systems.

Another conclusion that I would like to make is, you can ask the question: So what? What can we use this for? What have we learned? As you can see in the links below. We've provided a link to a video for an attachment for solving competitions challenges and it was using exactly the same principle. So it was accumulating energy in a fly wheel and it is using the energy to solve the challenge and because there is a rubber band and you know that in the beginning they exert more pressure than at the end and we have this rubber band that is connected to a fly wheel. At the beginning it accumulates some of the energy in the fly wheel and then the fly wheel acts as a source of energy and actually solves the challenge. Check out the link below. So that's the idea of this mechanism to be able to accumulate energy and use it at a later stage.

## Lessons with this tutorial

This tutorial is used in the following lessons