Answer:
f3 = 102 Hz
Explanation:
To find the frequency of the sound produced by the pipe you use the following formula:

n: number of the harmonic = 3
vs: speed of sound = 340 m/s
L: length of the pipe = 2.5 m
You replace the values of n, L and vs in order to calculate the frequency:

hence, the frequency of the third overtone is 102 Hz
Answer:
v1=18.46m/s
v2=29.8cm/s
Explanation:
We know that

the equation of the motion is

we can calculate w by using

Hence, we have that

the speed will be

hope this helps!
Answer:
It is possible to statically charge objects by rubbing it against carpet fibers, but I'm not sure if that was in the article that you read.
Explanation:
Static charge can build up via carpet fibers.