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# Physics question watch

1. Attachment 612018
Can someone tell me how to answer the second question please. I really don't understand it.
2. (Original post by AspiringUnderdog)
Can someone tell me how to answer the second question please. I really don't understand it.
Guess you've had a failed attachment... I can't see anything
3. (Original post by Joinedup)
Guess you've had a failed attachment... I can't see anything
Sorry, I've fixed it now.
4. bump
5. (Original post by AspiringUnderdog)
bump
6. (Original post by Joinedup)
https://www.thestudentroom.co.uk/att...hmentid=612018

7. yeah.

so if you're happy with the velocity from the first part...

you're asked about the radius of the nozzle that's emitting 3.5 m3/s of water at 40 m/s

I'd suggest thinking about 1 seconds worth of water - which will be a cylinder of water 40m long and 3.5 m3 in volume.
can you find the cross sectional area of that cylinder?
8. (Original post by Joinedup)
yeah.

so if you're happy with the velocity from the first part...

you're asked about the radius of the nozzle that's emitting 3.5 m3/s of water at 40 m/s

I'd suggest thinking about 1 seconds worth of water - which will be a cylinder of water 40m long and 3.5 m3 in volume.
can you find the cross sectional area of that cylinder?
I'd asumme doing 3.5m^3/40m because the ms cancel out to m^2 but I don't think that that works...
9. (Original post by AspiringUnderdog)
I'd asumme doing 3.5m^3/40m because the ms cancel out to m^2 but I don't think that that works...
well 40m/s is quite fast and 3.5m3/s is actually not a very large rate for this type of scheme
e.g. http://www.fhc.co.uk/ffestiniog.htm
10. (Original post by Joinedup)
well 40m/s is quite fast and 3.5m3/s is actually not a very large rate for this type of scheme
e.g. http://www.fhc.co.uk/ffestiniog.htm
Would I be able to divide the volume by the height though? The numbers probably don't make sense for reality because it's some dodgy question from online.
11. (Original post by AspiringUnderdog)
Would I be able to divide the volume by the height though? The numbers probably don't make sense for reality because it's some dodgy question from online.
Yeah - well I wrote it as volume divided by length to make sure it didn't look like I was using the difference in altitude between the inlet and outlet in that calculation.
12. (Original post by AspiringUnderdog)
Would I be able to divide the volume by the height though? The numbers probably don't make sense for reality because it's some dodgy question from online.
It would be worth searching for volumetric flow rate and seeing if there are any good online resources to help understand the concept.

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