1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

2 Sound waves reflection easy problems

  1. Oct 2, 2016 #1
    1. The problem statement, all variables and given/known data
    Refer to the photos, question 21 and 22(the one with a helicopter)

    2. Relevant equations
    Both answers are A

    3. The attempt at a solution
    for question 21, if the counts to ten, there are 9 intervals. I divide 20 by 9 and divide it again by 2 and get 1.1s not 0.5s.
    for question 22. I think it is C. Because the first reflected pulse has travelled 2h and the second reflected pulse has travelled 4h. I think it is impossible for the answer to be A, the pulse should travel slower in water.
     

    Attached Files:

  2. jcsd
  3. Oct 2, 2016 #2

    lewando

    User Avatar
    Gold Member

    For Q21, if the first clap is associated with the count of zero, wouldn't there be 10 intervals?
    For Q22, the speed of sound in water is greater than the speed of sound in air.
     
  4. Oct 2, 2016 #3
    But 20/10(2) = 1s?
     
  5. Oct 2, 2016 #4

    lewando

    User Avatar
    Gold Member

    That is true. That result matches answer B. I can't see how A could be correct.
     
  6. Oct 2, 2016 #5

    lewando

    User Avatar
    Gold Member

    Actually I misread the question. Only claps are being counted.
     
  7. Oct 2, 2016 #6
    Oh thanks I can do it now
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: 2 Sound waves reflection easy problems
  1. 2 sound wave problems (Replies: 2)

  2. Sound Wave Problem (Replies: 6)

Loading...