The rule of balance of the lever underlies the action of various kinds of tools used in technology and everyday life so that gain in strength or path is required. We have a gain in strength when working with scissors, a shovel, and paddling. Levers of various types are available on many machines, pedals or a handbrake on a bicycle, an arrow on a crane.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.