Definition of Lever

Lever is the simplest machine in the world. It is a rigid bar, which can be rotated about a fixed point.

And that the book can be read with the ears? – People who are not familiar with modern technologies may ask my previous articles and sections of this book. – It is possible and necessary. Now it is worth dwelling on a cursory analysis of the advantages and disadvantages of perception, working out textual information with the help of sight and hearing. Because It seems to me that all people who want to learn, develop and improve should start with these fundamental questions