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08 Mar 21
A produce seller sets 200 kg of cucumbers out at the start of the day in a street market. The cucumbers are initially 99% water. Its a very hot day, and unfortunately they have made no sales. At the end of the day when they are pulled off the shelf the cucumbers have dried out some. They are now 98% water. What is the total mass of cucumber remaining at the end of the day?
08 Mar 21
@joe-shmo said200 kg.
A produce seller sets 200 kg of cucumbers out at the start of the day in a street market. The cucumbers are initially 99% water. Its a very hot day, and unfortunately they have made no sales. At the end of the day when they are pulled off the shelf the cucumbers have dried out some. They are now 98% water. What is the total mass of cucumber remaining at the end of the day?
Change of state does not affect mass.
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08 Mar 21
3 edits
@venda saidIt does if that mass evaporates out of the cucumber? If you put the cucumbers on a scale at the end of the day, you are going to measure lower weight ( mass ) than what you had at the beginning of the day.
200 kg.
Change of state does not affect mass.
08 Mar 21
@joe-shmo saidMass and weight are not the same thing.
It does if that mass evaporates out of the cucumber? If you put the cucumbers on a scale at the end of the day, you are going to measure lower weight ( mass ) than what you had at the beginning of the day.
08 Mar 21
@joe-shmo said100 kg
A produce seller sets 200 kg of cucumbers out at the start of the day in a street market. The cucumbers are initially 99% water. Its a very hot day, and unfortunately they have made no sales. At the end of the day when they are pulled off the shelf the cucumbers have dried out some. They are now 98% water. What is the total mass of cucumber remaining at the end of the day?
2 kg dry mass is 1% at the start of the day and 2% at the evening.
If 2kg are 2% whole mass is 100 kg.
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@ponderable saidCorrect Ponderable!
100 kg
2 kg dry mass is 1% at the start of the day and 2% at the evening.
If 2kg are 2% whole mass is 100 kg.
I like this because intuitively this seems surprising on the surface. An seemingly innocuous percent change in the fraction of the cucumber that is water, leads to very large change in overall mass of the cucumbers!
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08 Mar 21
1 edit
@venda saidYeah. I know, but that turns out to be irrelevant here. The weight is just a scalar multiple of the mass for this type of problem.
Mass and weight are not the same thing.