Answer: In a longitudinal wave, the crest and trough of a transverse wave correspond respectively to the compression, and the rarefaction. A compression is when the particles in the medium through which the wave is traveling are closer together than in its natural state, that is, when their density is greatest.
Because the same sides(N and N, or S and S) are facing each other in magnet 4 and 5. Also in magnet 2 and 3.
The correct answer is "3. Both increase"
In fact, the frequency of a vibrating string is given by

where L is the length of hte string, T the tension and

the linear mass density.
We can see that string is made shorter, L decreases, so the frequency f increases. And since the pitch has the same behaviour of the frequency, it increases as well.
Answer:
1328.7032 kg
Explanation:
P = Pressure = 112 kPa
T = Temperature = 285 K
V = Volume = 7023 m³
R = Gas constant = 8.314 J/mol K
From the ideal gas law we have

The mass of gas is given by

The mass of helium in the blimp is 1328.7032 kg