A balloon is fitted over the open end of a glass beaker that contains water. The beaker is placed over a flame, which heats the water. At the same time,
the balloon is squeezed, so that it deflates. What are the correct signs for the
heat and work changes to the beaker and balloon system?
A. -Q, +W
B. -Q, -W
C. +Q, +W
D. +Q, -W

Well i am not very good at this but  i would be guessing 1hope i  

The correct option is this: the sound waves from the two trombones have slightly different frequencies.from the question given above, we are told that the loudness of the sounds were increasing and decreasing, this is because the frequencies of the two sounds are different. the means that the number of waves that pass a fixed point in a given amount of time differ for both sounds.