Index of Refraction

Honors Physics went over their Chapter 6 exams and then moved into the tangential speed and acceleration associated with rotational motion. The variation in tangential speeds between inner and outer regions of a rigidly-rotating body are what make the consistent angular speeds possible. We then added a third acceleration to the mix – centripetal acceleration. Directed towards the center of the rotation, centripetal acceleration takes the job of changing the direction of motion and keeping objects moving in a circle. The speed of the motion is handled by the tangential acceleration. So, two different accelerations work to produce the velocity changes – tangential for speed, centripetal for direction. Tomorrow, we discuss the forces that produce centripetal acceleration – centripetal force – and demonstrate how different forces can take on that role for circular motion.

Physical Science B and E went over their fluid forces exam. For this exam only, since it was pretty math-heavy and much of the material was not in the textbook (although it was in the class notes), I am allowing test corrections. As stated in class – for conceptual questions, tell me why you chose the wrong answer and explain why the correct answer is actually correct; for problems - show the work to solve the problem correctly and discuss why you got the problem wrong in the first place. For each item you correct correctly, I’ll give you back one-half of the points you missed. For both classes, get all the help you need from me, parents and friends, but have the corrections to me on Thursday.

Physics F conducted their centripetal force lab. You will have time in class tomorrow to complete the lab and its write up, but you might spend a little time tonight organizing your data to make tomorrow run more efficiently.

Physics G completed their work on the centripetal force lab. For two different constant radii, an increase in the centripetal force required a higher tangential velocity for the motion to proceed. Comparing trials with the same mass, the larger radius required a higher tangential velocity to keep the motion going. We will review tangential and angular speeds and accelerations tomorrow and toss centripetal acceleration and centripetal force in to the mix.

Homework

Honors Physics A: Complete Practice 7G and 7H
Physical Science B and E: Work on test corrections
Physics F: None
Physics G: Complete the 7.2 Section Review and p. 270 # 17,18,20