**Description**: Interactive flash animation to simulate the measurement of speed in pendulum case: mesuring also the height of the ball, it's possible to know the kinetic energy and potential one.

**Instructions:**

The ball weighed: m = 100 g. Use g = 9,8 N.kg-1.

**a.** We compare the ball to a point-like object. Give the expression of its kinetic energy.

**b.** When using the chrono or a time interval marker (Dt constant), how do you asses the speed of
the object, for example A4 ?

**c.** Calculate Ek for each recorded position (except the two outliers). Record your results in a table.

**d.** Draw the graph of the evolution of Ek vs time.

**a.** Give the expression of the gravitational potential energy.

**b.** Calculate Ep for each recorded position (except the two extremes). Record your results in the table.

**c.** Draw the graph of the evolution of Ep vs time.

**a.** Plot the graph of E = Ek + Ep vs time.

**b.** Comment on the evolution of E.

**a.** Establish an inventory of the forces acting on the ball. What can be said about the work of forces other than weight ?

**b.** Draw a diagram of the energy exchange between the starting position and a position during the movement. Explain the evolution of E.

**c.** Were the results of this measurement applicable to a large number of the oscillations ? Justifiy.

**Definition**:

__Simple pendulum__: Hypothetical pendulum suspended by a massless and frictionless thread of constant length.