Go to: Course homepage, Lectures

Informal sessions:

o Tu 3:30-4:20pm, RAS 218;

o Fri 4-4:50pm, ECJ 1.204.

Lecture 35(iq31)

Qualitative description of waves

Transverse traveling waves

· Fixted t: Sinusoidal pattern in x, l, k=2p/l

· Fixed x: SHM in y, T, w=2p/T

· Fixed q: v=w/k=l/T.

Wave speed: v=(F / M/L)^1/2.

Superposition of 2 waves

· y=2A cos[|q₁-q₂|/2]cos[|q₁+q₂|/2]

Beats

· y=2cos[Dwt/2]cos wt

· | DwT_beat/2|=p àf_beat=|f₂-f₁|

Standing waves

Reminders and announcements:

· Read chapters 16. Begin HW13.

· Will there be a walk on Wed 11/26? No, I expect to hold our class on that day. On that day, I plan to have our regular iq-sessions. However, I have decided to increase the iq-drops from 4 to 5. So those who are present will earn a bonus iq-credit. On the other hand, those who are absent will not be penalized as far as the iq-credit is concerned.

· Unit 4 is relatively easy material please read the remaining chapters ahead of the lectures.

§ Plan to complete hw13 by this weekend.

§ Lecture material for hw14 will be covered mainly on this Friday and next Monday. Plan to complete hw14 as much as possible before leaving for Thanks giving holidays.

· Due to a schedule conflict there will be no the instructor’s informal session this Friday.

· The due date of HW14 will be on 4am, Tuesday, Dec. 2. (Notice that there is an update in our syllabus)