To proof of students with tope of hygiene and encapsulado in carcasa solid of aluminium. This sensor has been designed of intelligent way to be hanged of an anilla or entered in a wand of a support of laboratory. It measures bisteeringal strengths of until 50N. It supplies with a dock of 20N/m and a set of accessories for fixation. For the study of the laws of Newton, rozamiento, impulse, strength centrípeta, conservation of the power, etc