Solve .
water wheel has a 30-ft diameter. to get a good approximation of the speed of the river, you count the revolutions of the wheel and find that it makes 20 revolutions per minute(rpm). what is the speed of the river, in miles per hour?
Helpp

Question

Solve .
 water wheel has a 30-ft diameter. to get a good approximation of the speed of the river, you count the revolutions of the wheel and find that it makes 20 revolutions per minute(rpm). what is the speed of the river, in miles per hour? 
Helpp

anonymous · Answer

so if there was no water passing faster than the wheel then, it would be like turning a carpet with some spike wheel: in that case, the length of carpet that you bring forward is exactly the circumference that you were having on ground

anonymous · Answer

like when you turn a pizza that was put on a wheel and you make half a turn, then half the length of circumference is already laid out

anonymous · Answer

if you have diameter you can calculate the circumference of the wheel, and then you know how "length" of water was passing by

anonymous · Answer

I dont got it

anonymous · Answer

we need circumference
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anonymous · Answer

because circumference is how much water is passing

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