Education Technology

# Activities

• ##### Subject Area

• Math: Precalculus: Trigonometry (Triangle and Circular Functions)

9-12

• ##### Activity Time

20 - 30 Minutes

• ##### Device
• TI-83
• TI-83 Plus Family

CBR™/CBR 2™

• ##### Other Materials
• A pendulum bob attached to string approximately 1 metre in length.
• A 20 ? 30cm diameter fishing buoy makes an excellent pendulum, they generally have a pre-drilled hole through the centre for attaching the string.

## Grandfathers Equation

#### Activity Overview

The beauty of a Grandfather clock is not just in the casing; the motion of the pendulum is often admired. Without the pendulum swing the mechanics of the clock might just as well be electronic in nature. Many aspects relating to the motion of a pendulum swing can be modelled mathematically.

#### Before the Activity

The first stage in modelling the motion is to collect some data. The Calculator Base Laboratory or CBR™ is a motion detector that can be connected to a TI-83 (plus) calculator. The position, velocity and acceleration at any time are recorded in the calculator's Stat. - List editor. The data can be used to draw graphs of the ball's motion. The motion of the pendulum in this series of investigations in only considered in a single horizontal plane.

#### During the Activity

See the attached PDF for detailed instructions.

#### After the Activity

See the attached PDF for detailed instructions.