Today we worked on some AP practice problems involving gravitation. The detailed solution to 1977M3 is in the ch13 folder. Make sure you a draw a picture and understand what the variables in each formula represent. For example, Newton's law of gravitation contains an "r" AND the formula for centripetal acceleration also contains an "r", BUT the "r"s do not have to have the same value in each formula. To understand their values, you NEEEEEEEED to draw a picture and understand the quantity that the variable refers to!!!!! For homework, begin working on the multiple choice questions, and also do FR 1984M2 and 2005M2.
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Today we talked about Kepler's Laws (make sure you know them!). We also clarified some confusion with finding gravitational potential energy for objects that are far away from the earth. Homework is p. 405 #12-16. Tomorrow's homework (if you want to get a jump on it) is p. 405 #17-24. There will be a quiz on Friday on gravitation. Solutions to the homework are in the google folder for CH13. You can look them up if you get stuck.
Answers: p. 405 #12-16: 12. 38.8m 13. 6.02x10^4 m/s 14. vfinal=9988.4 m/s 15. vinitial=4.21x10^4 m/s 16. r planet = 1.8x10^7 m ; v=9.4147x10^3 m/s p. 405 # 17-24 17. r asteroid=4.37x10^11m; v=1.74x10^4 m/s 18. Msun=2.01x10^30 kg 19. M p=1.48x10^25 kg; M s=5.2x10^30 kg 20. a) T1=T2=15000s; T3=27556.76s; b) F2=20000N; F3=4444.4N c) KE1/KE3=1.5 21. r=2.93x10^9 m 22. T=91.3 min = 5480.6 seconds 23. T = 4.19 hours 24. altitude = 1.72x10^7 m Today we solved some gravitation problems together. No homework tonight as we did not get far enough to cover any new topics.
Today we learned about Newton's law of gravitation, the difference between g and G, and how we are able to find the mass of the earth. Homework is p. 404 Concept QUestions #1-3, 5,6 and Problems #1,2,5-11odd. Answers are in the back of the book. I am not posting fully worked solutions for a couple of day so that you can get these problems on your own before you look at solutions.
Today we did test corrections for yesterday's test. Tomorrow we being Chapter 13: Gravitation!
Test on Chapter 12 is Monday. There are many concepts in this chapter, make sure to review all of them carefully. The two practice tests will not be collected, they are to help you review and prepare for the test. The falling toilet paper rolls lab will be collected on Monday (you need to solve the problem and film your trial to show if your solution was correct.)
Topics covered on the exam: Rotational kinematics Calculation of center of mass (for a system of object, or for a solid object) Rotational energy calculating moment of inertia for a system of particles or for a regularly shaped object parallel axis theorem torque Net torque Couples Rotational dynamics Rotation about a fixed axis Constraints due to ropes and pulleys static equilibrium stability rolling motion (rolling constraint) finding KE of a rolling object finding ME of a rolling object (ME includes gravitational PE, KE translational, and KE rotational) angular velocity vector (how to find direction) cross products angular momentum conservation of angular momentum Today we saw some demos with angular acceleration and we saw that the rotating end of a meter stick actually accelerates at a rate greater than g. Students were able to calculate the point on the meter stick where the acceleration exceeds g. Thanks Todd, Quinn, and Will for filming the eraser demo. Today we learned about angular momentum. Homework is p. 380 #46-50, 69, 85, 86, 89. Solutions are posted in the ch12 folder on GD. Our unit test will be on Monday 3/21. We will be doing whiteboard review problems and "lab" problems for the next few days.
Today we talked about rolling motion. Homework is p. 380 #35-40 (if you get too confused with #40 go ahead and skip it), 51, 54, 55, 67. Solutions are posted in GD. The solutions to Fridays homework are also found in GD.
Today you gathered your data to calculate the moment of inertia of a step pulley. The lab is due Tuesday. The other homework from Wednesday and Thursday is due on Monday.
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REMINDERs:Chapter 2 test retake is Monday 10/15. You can take the retest either before school or after school, but you must complete all of the Chapter 2 homework (75% completion on each assignment) to be eligible for a retake!
Resources:Review videos - excellent videos covering all AP Physics C content.
Viren's Videos (another good source of videos) Study guides/review guides by topic. Archives
October 2018
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