A Day for Machines

Honors Physics conducted a lab investigation that targeted mechanical advantage and efficiency of levers and pulleys. First and third class levers were tested, with both IMA and AMA calculated and compared. As expected, first-class levers can produce mechanical advantages greater than one, but third-class levers always produce mechanical advantages less than one. Also, the actual mechanical advantage (AMA) was significantly less than the ideal mechanical advantage (IMA) due to friction in the system. Simple fixed pulleys, movable pulleys and pulley systems were then constructed and tested. The results bore out that the simple, fixed pulley has a MA roughly equal to 1, a simple movable pulley has a MA close to 2 and pulley systems have mechanical advantages equal to the number of supporting cords. Have these labs written up for tomorrow, so that we can go over them along with the review worksheet in preparation for Wednesday’s exam.

Physical Science B discussed their tossed ball lab and how it demonstrated conservation of total energy and conservation of mechanical energy. The basketball conserved mechanical energy better than did the balloon, but total energy was conserved in both (and in all) cases. Students then reviewed the basics of conservation of energy and efficiency. Tomorrow, time will be spent reviewing for the exam on Wednesday. Look over the material tonight and come ready with questions.

Physical Science E discussed their conservation of mechanical energy problems and then began work on review material for Wednesday’s exam. We’ll go over this work tomorrow prior to engaging in a general review of the chapter. Make sure to look over the chapter and come to class tomorrow with any questions or problems.

Physics F and G reviewed properties and examples of the lever family and then moved into a discussion of the inclined plane family. The simple inclined plane, the wedge and the screw increase input distance to reduce effort force. Tonight, flesh out your list of members of the inclined plane family and be ready to share that list in class tomorrow. We will finish this chapter this week and the exam looks like it is going to fall on Monday. Budget study time accordingly.

Homework

Honors Physics A: Complete lab write up
Physical Science B and E: p. 411 #21-23 and p. 412 #26,26
Physics F and G: Prepare a list of 20 members of the inclined plane family and complete items #1,3,4,5 of the 8.4 Section Review