This article reports a comparative study of the velocities of rolling of a steel sphere on an inclined plane with an angle of launching. To determine the final velocity in the inclined plane, we used stopwatches with digital sensors, and to determine the initial velocity on the oblique launch, we used the horizontal range equations. From the graph of the velocity as a function of the square root of the height of the inclined plane it was possible to determine the range of compatibility between the first two modes to determine the speed of the sphere and make comparisons with a third mode, in which case it was supposed the conservation of mechanical energy. From the same type of graph, it was possible to determine the start conditions of sliding, and the coefficient of friction between the sphere and the inclined plane, with consistent results with other simple methods.
rolling of a sphere; frictional coefficient; oblique launching
