A bob (small ball) is attached to the lower end of a cord that is attached to the cieling and moves in a horizontal circle at a constant speed. (The cord sweeps out a cone as the bob rotates.) The bob has a mass of 0.040 kg, the cord has a length L = 0.90 m and a negligible mass, and the bob follows a circular path of circumference 0.94 m. What are (a) the tension in the string and (b) the period of the motion?