3-5-09

Today's class started off with the daily question. The daily question involved rolling three rounded objects down two meter sticks. One of these rounded objects had a consistent radius throughout it's body, another had a radius that decreased as it got closer to the center of it's body, and the third had a radius that increased as it got closer to the center of it's body. The one that proved to be more stable was the one with the larger radius in the center. This is due to the direction that the two cups (each rounded object was constructed of cups) were turning as they rolled down the track of meter sticks. The two cups turned toward the center as the moved down the track; as one cup would turn to the center and create an angle on the track, the other would turn toward the center to meet that angle and straighten out. The two cups continue to correct themselves and become straight again through the travel to remain stable.

Next, on today's agenda was a homework check. Last night, the students had to complete page 4 for homework. This multiple choice page dealt with rotational motion. The answers are: B, A, B, A, C, E, D, C. And for number 9, the rotational speed is 2.5 rev/s, and the tangential speed s 9.42 m/s.

After reviewing the homework, we had a demo. The demo involved a toy car to demonstrate which direction the force being applied to the car on a string going in a circle is. The force was proven to be inwards, as the car is pulling outwards.

Class finished with a lab about centripetal forces (pages 5-8).


 * SHORT QUIZ TOMORROW!!!!!!**