Hello, I need help on these questions 13,19 and 21. Work would be so appreciated so I can understand thank you so much for your time!

21. [-/2 Points] DETAILS SERPSE10 15.5.P.017. 0/6 Submissions Used A simple pendulum makes 112 complete oscillations in 3.50 min at a location where g = 9.80 m/s2. (a) Find the period of the pendulum. S (b) Find the length of the pendulum. m Need Help? Read It13. [0/3 Points] DETAILS PREVIOUS ANSWERS SERPSE10 15.3.OP.013. 1/6 Submissions Used MY NOTES ASK YOUR TEACHER A plastic ball attached to a spring moves in simple harmonic motion. The amplitude of the ball's motion is 13.0 cm, and the spring constant is 5.00 N/m. When the ball is halfway between its equilibrium position and its maximum displacement from equilibrium, its speed is 25.6 cm/s. (a) What is the mass of the ball (in kg)? 1.2512 X What is the total energy of the spring-mass system in terms of amplitude? How is it related to the kinetic and potential energies? What is the position of the ball in terms of amplitude? kg (b) What is the period of oscillation (in s)? 1.5723 X How is the period related to the mass and spring constant? s (c) What is the maximum acceleration of the ball? (Enter the magnitude in m/s2.) 2.0759 X How is the maximum acceleration related to angular frequency and amplitude? m/s2 Need Help? Read It19. [-/2 Points] DETAILS SERPSE10 15.5.OP.025. 0/6 Submissions Used MY NOTES ASK YOUR TEACHER A meter stick is attached to one end of a rigid rod with negligible mass of length / = 0.622 m. The other end of the light rod is suspended from a pivot point, as shown in the figure below. The entire system is pulled to a small angle and released from rest. It then begins to oscillate. (a) What is the period of oscillation of the system (in s)? (Round your answer to at least three decimal places.) (b) By what percentage does the period of the system found in part (a) differ from the period of a simple pendulum 1.122 m long? IT simple - system x 100% = % simple