tag:blogger.com,1999:blog-5088860151651047897.post501299542026204811..comments2024-03-25T10:56:59.380-04:00Comments on Jacobs Physics: Do I need to know about pressure/displacement nodes in AP Physics 1?Greg Jacobshttp://www.blogger.com/profile/03854009948036330746noreply@blogger.comBlogger1125tag:blogger.com,1999:blog-5088860151651047897.post-89398161385382337652018-04-23T20:04:52.445-04:002018-04-23T20:04:52.445-04:00For the record, from the AP Physics 1 Course and E...For the record, from the AP Physics 1 Course and Exam Description:<br /><br />6.D.3<br />b) b. For standing sound waves, pressure nodes correspond to displacement antinodes, and vice versa. For example, the open end of a tube is a pressure node because the pressure equalizes with the surrounding air pressure and therefore does not oscillate. The closed end of a tube is a displacement node because the air adjacent to the closed end is blocked from oscillating.<br /><br />I don't really think they'll ask about the *names* "pressure node" and "displacement node." What I do think could happen is that they could ask some conceptual question about the air being "free to move/oscillate" at certain points, and they could certainly have Student A draw a pressure standing wave representation and describe it as a displacement one, and make the student pick apart what they got right and what they got wrong.<br /><br />What's tricky about this (beyond the concept, anyway) is that there are a LOT of textbooks that only present one or the other--the pressure wave or the displacement wave, but not both. And whichever one they include, they often just call it a "standing wave" and leave it at that. So the inconsistency among official sources may (or may not, for all I know) make this particular topic not the fairest to ask about; any question on it will favor students who had one brand of text or e-text instead of another.Willnoreply@blogger.com