Machines

Physics B and F began their lab unit on machines. The inclined plane, all three classes of simple levers and various pulley configurations will be tested for efficiency, actual mechanical advantage and ideal mechanical advantage. Students will also get a good chance to really see how these machines function to make work easier. Pretty much every group finished or nearly finished the inclined plane portion, so levers should be on the docket tomorrow. For inclined planes, it was quite clear that the effort force was less than the output force (weight of the load), but amount of work input was greater than the work output. Such is the cost of using a machine...

Honors Physics completed their discussion of impulse and momentum and we took time to review the lab and go over the impulse-momentum homework problems. Attention then turned to one of the biggies in physics - the law of conservation of momentum. The total momentum of a system remains constant in the absence of outside forces. Whatever momentum is lost by one object, that momentum is gained by someone else and vice versa. We discussed how conservation of momentum is mandated by Newton's 3^rd Law of Motion, which can be extended to say that the impulse experienced by two objects in a collision are equal in magnitude, but opposite in direction. We'll look at momentum conservation more tomorrow, before moving on to types of collisions.

Physical Science went over their impulse-momentum problems and it was clear that a little more work was needed. So, students have to create their own worksheet for momentum and impulse-momentum problems, script an answer key and be prepared to share their worksheet with others tomorrow in class.

Homework

Honors Physics: Practice 6D and the 6.2 Section Review #2, 4
Physics B and F: None
Physical Science: Self-created momentum and impulse-momentum worksheet and answer key