A pendulum consists of a 3.8 kg stone swinging on a 3.6 m string ofnegligible mass. The stone has a speed of 9.4 m/s when it passesits lowest point. (a) What is the speed when the string is at 64° to the vertical? (b) What is the greatest angle with the vertical that the string will reach during the stone'smotion? (c) If the potential energy ofthe pendulum-Earth system is taken to be zero at the stone's lowestpoint, what is the total mechanical energy of the system?