Physics FOR THE IB DIPLOMA Waves Activity: Simple harmonic motion energy graphs The following graphs will all have ‘Time, t’ on the x axis. Label the y axes of the three graphs ‘Kinetic energy/J’, ‘Potential energy/J’ and ‘Total energy/J’. Set a pendulum in motion with a suitable length so that it oscillates with a frequency and speed that are easily observed. Observe the pendulum. Questions 1 At what displacement is the velocity at its maximum? ______________________________________________________________________________________ 2 At what displacement is the velocity zero? ______________________________________________________________________________________ 3 Where will the kinetic energy be a maximum and where will it be zero? ______________________________________________________________________________________ ______________________________________________________________________________________ 4 Sketch the curves on the axes on the next page. 5 In what way do your sketches not describe perfectly the pendulum’s energy values? ______________________________________________________________________________________ 6 How might you change your curves to show this? ______________________________________________________________________________________ © Colin Cuthbert/Hodder & Stoughton Limited 4 1