[url=https://phet.colorado.edu/sims/html/gravity-force-lab-basics/latest/gravity-force-lab-basics_ru.html]https://phet.colorado.edu/sims/html/gravity-force-lab-basics/latest/gravity-force-lab-basics_ru.html[/url][br][br]Благодарность:[br]PhET Interactive Simulations[br]University of Colorado Boulder[br][url=https://phet.colorado.edu/]https://phet.colorado.edu[/url]