Hmmm . . . Nope. :$
I asked my friend and she told me that we must always use 8 for folding. :/
no, i guess she's wrong here.
(b) An aluminium cooking foil manufacturer states that the thickness of the foil is 15 ?m.
You have a micrometer which can read to a precision of 0.01 mm.
(i) Describe how you would try to find an accurate value for the thickness of a sheet
of the foil.
Now, look the precision of micrometer is 0.01 mm. so that's the LEAST value it can read.
and, since the sheet is 15 MICROMETER, we first convert this into milimeter
15 micrometers = 0.015 millimeter
now, we need to fold the sheet so that the screw gauge(micrometer) can be used to read it.
so, try the following
fold the sheet into 2 > 0.015 x 2 > 0.03
fold the sheet into 5 > 0.015 x 5 > 0.075
fold the sheet into 7 > 0.015 x 7 > 0.105
fold the sheet into 8 > 0.015 x 8 > 0.2since the one in bold is close to the precision of micrometer (0.01) we fold that sheet 8 times and read the value
why we don't take 7 folds > 8 is easier and taking 7 will be too close to the precision of micrometer (0.01).
therefore. 8
get it?
