(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A food packaging factory is moving soup through a [itex]0.075 m[/itex] diameter pipe when an obstruction occurs in the pipe. An ultrasound probe, connected to an oscilloscope, is moved along the pipe to find the obstruction (Figure 1). The oscilloscope trace is shown below

(Figure 2).

Figure 1:

Figure 2:

Oscilloscope time base = [itex]20 \times 10^{-6} s \ cm^{-1}[/itex]. On figure 2, pulse A is the outgoing signal from the probe and pulse B is the reflected signal from the other side of the pipe, Calculate the speed of the ultrasound in the liquid in the pipe.

2. Relevant equations

[itex]v = \frac{s}{t}[/itex]

3. The attempt at a solution

I understand which formula to use but I am struggling to obtain values from the graph shown. The wording has confused me. I would have thought that the time is [itex](6) \times (20 \times 10^{-6})[/itex] but it is incorrect.

The correct calculation is:

[itex]v = \frac{s}{t}[/itex]

[itex]= (150 \times 10^{-3} \ \mathrm{(m)}) \div (132 \times 10^{-6} \ \mathrm{(s)})[/itex]

How did the mark scheme obtain the value for the calculations? Thanks in advance.

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# Ultrasound Calculation

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