Go Back   Physics Help Forum > High School and Pre-University Physics Help > Thermodynamics and Fluid Mechanics

Thermodynamics and Fluid Mechanics Thermodynamics and Fluid Mechanics Physics Help Forum

Reply
 
LinkBack Thread Tools Display Modes
Old Dec 7th 2009, 02:12 PM   #1
Junior Member
 
Join Date: Dec 2009
Location: MN
Posts: 14
problem on volume flow rate

A pump is used to empty a 6000 L wading pool. The water exits the 2.5 cm diameter hose at a speed of 2.1 m/s. How long will it take to empty the pool?

First thing I did was convert to meters
6000 L = 6 m^3 (I think LOL)
2.5 cm = .025 m

First equation I used is Av=Q .025*2.1=.0525 m^2/s The problem is that my book says that Q should be measured in m^3/s which will make sense if I continue but I'm getting m^2/s. What am I dong wrong?
A=cross-sectional area of tube
v= velocity
Q= volume flow rate


Next I would use Q=Volume/Time=> Time=volume/Q T=6m^3/.0525m^2/s
Book is offline   Reply With Quote
Old Dec 7th 2009, 10:43 PM   #2
Physics Team
 
Join Date: Feb 2009
Posts: 1,425
Firstly Area x vel = (meter x meter) x meter / sec = meter^3 / sec.
= vol/sec

First find the volume flow rate i.e. how many m^3 leave the pool per sec.

Let this be say v .

Then divide 6 by v to get the time.

I think your problem is that you have not calculated the area which should be

pi d^2 / 4 or pi r^2 .

You have used only the dia instead.
physicsquest is offline   Reply With Quote
Reply

  Physics Help Forum > High School and Pre-University Physics Help > Thermodynamics and Fluid Mechanics

Tags
flow, problem, rate, volume



Thread Tools
Display Modes


Similar Physics Forum Discussions
Thread Thread Starter Forum Replies Last Post
Finding flow rate ling233 Advanced Mechanics 0 Apr 27th 2016 06:28 PM
volume flow rate ling233 Advanced Mechanics 3 Jan 17th 2016 05:18 AM
flow rate and velocity robhare General Physics 1 Apr 25th 2011 10:20 AM
Help With Finding Flow Rate Please!!!! alexito01 Thermodynamics and Fluid Mechanics 3 Mar 11th 2009 08:32 AM
Flow rate Devlan Thermodynamics and Fluid Mechanics 0 Nov 10th 2008 08:48 AM


Facebook Twitter Google+ RSS Feed