On pages 67, 68, and 68R we investigate uniform circular motion. Page 68 is an orbit experiment, and 68R is an extra-help page for interpreting its results.

The Chapter 7 Review Sheet should be started now.

On page 68b we discover the small-angle theorem.

On page 69 we discover the centripetal acceleration formula by a geometric approach and figure out the exact value of the proportionality constant in the empirical version that we discovered on 68. On 69b more advanced students can discover how averaging can reduce the uncertainty of repeated measurements.

On page 70 we investigate simple trajectories.

On pages 71 and 72 we discover how motion can have both tangential and centripetal accelerations and we summarize the basic principles of trajectories.

On pages 73 and 73b there are some practice exercises.