Misurazione di grandezze cinematiche con un personal computer on-line

An automatic device for studying motions is described in this paper. The device consists of a dynamics cart carrying a phototransistor that receives the light reflected by a sheet of paper whit black and white stripes, on which the cart perpendicularly moves. The electric signals generated by the phototransistor as it passes in front of the two kind of stripes is sent, after amplification, to an Apple II+ computer. The number of transitions per second, i.e. the speed of the cart, is counted by the computer via software. Speed, distance and acceleration can be shown on the screen of the computer itself.