A single pulley has no advantage in reducing force. A single pulley only helps by changing direction of effort, pulling something from up to down feels easier then vice versa due to our muscles arrangement. However, the force needed is the same.
Meanwhile multiple pullies divide the tension. The lower pulley itself reduces the force into half so as to you feel a part of the tension while rest is suspended by the ceiling in the case in the diagram below.
Answer:
8.40 m/s
Explanation:
Slope of the plot is 0.119
Slope of a plot is given by the change in y direction divided by the change in x direction
Here, the y axis represents inverse wavelength and the x axis represents frequency.
f = Frequency (Hz, assumed)
v = Phase velocity (m/s, assumed)
λ = Wavelength (m, assumed)
So, slope

Now,


The speed of sound travelling in the tube is 8.40 m/s
The correct answer would be 1.375 < t < 3 i hope this helps anyone