Learning the Resistance Coefficients of Pendulum Motion Using Balls of Various Sizes

In order to obtain the damping and resistance coefficients of a pendulum, we constructed an optical system containing photogate for measuring speed pendulum at lowest point motion. The consisted photoresistor, laser, mechanical body, ball. A 3D printer was used produce body balls various sizes. Furthermore, Arduino automate measurement motion increase precision. We found that coefficient proportional size balls, regardless ball mass, in agreement with drag equation small Reynolds number.