mak: a horizontal pipe of 50mm has fuel flowing through to a depth of 40mm.
if the angle at the centre POQ, is 2.74 radians find the length of the arc PQ, in contact with the fuel
This question sounds terrible but I think it is quite easy.
Have you actually drawn the picture? It is the cross section of the pipe that you are interested in. And you do need to draw it.
The 40mm depth is not needed (I will just assume that it is accurate)
I suppose you can assume that 50mm is the internal diameter of the pipe.
Now, think in degrees first, you will probably find that easier
You know that there are 360 degrees in a circle.
If you had a sector with an angle of 20degrees at the centre then you would have 20/360 of a circle. does that make sense?
There are 2*pi radians in a circle. You have 2.74 radians. How much of the circle will that be. How much of the total circumference will that be?
You know that the circumference of a whole circle is 2*pi *r
What will be the circumference of the major arc that you are after?
Have a go at doing it yourself. If you need more help you can post again.
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