Fig (a) If the stopper moves in a horizontal circle, but the string is not perpendicular to the pipe, can you figure out the radius? Fig (b) 25 cm Radius Analysis 1. Why does increasing the tension force decrease the period of revolution? 2. If the stopper moves as shown in the figure (b) above, is the centripetal force still equal to the tension force? Draw a free body diagram to help you see. Is it less than or more than the tension force?

Fig (a) If the stopper moves in a horizontal circle, but the string is not perpendicular to the pipe, can you figure out the radius? Fig (b) 25 cm Radius Analysis 1. Why does increasing the tension force decrease the period of revolution? 2. If the stopper moves as shown in the figure (b) above, is the centripetal force still equal to the tension force? Draw a free body diagram to help you see. Is it less than or more than the tension force?