Today involved notes and demonstrations; trying to fill in some gaps on the homework as well.
We learned two big things that were new, Power and Percent Efficiency.
Power is defined as Joules per second, and can be relating energy used or work done per second.
I decided to give up on having many of you make your own equations from the units, so here it is:
Power = Work / Time
Finally, percent efficiency relates the input and output work of a machine. Ideally these are equal, and we'll pretend they are for some of our labs, but in the real world friction converts energy into thermal E.
When you divide input and output work, you should always get a percent less than 100. If you get something like 150% efficient, either you've discovered the next billion dollar idea or you need to flip your numerator and denominator. (take the reciprocal!)
Finish up the homework to the best of your ability. The page 149 problems should be easy. Try your best on the p.881 problems, using the chapter. Some of these will seem easier after tomorrow.
Science fair review committee / deadline to submit the idea for a project Thursday!!!!!!
No comments:
Post a Comment