Pendulums

Pendulums Gizmo – Energy of a Pendulum Activity Questions 1. How does changing the following affect the period of a pendulum (increase, decrease, no affect) Mass of the bob _______________________ Length of the string ________________________ Gravity _____________________ Angle of release ______________________ 2. If you want to increase the period, what action could you take? 3. Take a look at the energy charts. How does the kinetic energy and the potential energy of a pendulum compare when the pendulum is at its highest point in its path? Lowest point in its path? 4. How does the total mechanical energy compare at the lowest and highest point? 5. How does the total mechanical energy compare at any point? 6. Does the total mechanical energy ever equal the kinetic energy? The potential energy? 7. How is the total mechanical energy affected by the changes in kinetic and potential enrgy? Assessment 6. Answer the 5 assessment questions at the bottom of the gizmo – these will be recorded as a classwork grade

Pendulums What affects the period of a pendulum? If you wanted to double the period, what action could you take?

The repetitive motion of the pendulum is reflected in the repetitive nature of the energy graph.

Pendulums 1. A simple pendulum consists of a bob of mass 0.085 kg attached to a string of length 1.5 m. The pendulum is raised to point Q, which is 0.08 m above its lowest position, and released so that it oscillates with small amplitude ϴ between the points P and Q as shown below. (a) On the figures below, draw free-body diagrams showing and labeling the forces acting on the bob in each of the situations described. i. When it is at point P ii. When it is in motion at its lowest position

Pendulums (b) Calculate the speed v of the bob at its lowest position. (c) Calculate the force on tension in the string (d) Describe one modification that could be made to double the period of oscillation.