What is the Volume Flow Rate?

Question

Liquid flows through a 1.0 cm diameter tube at a rate of 7.0m/s. What is the volume flow rate in this tube, in m^3/s

I somehow keep getting is wrong. Isn't volume flow rate = (velocity)(area)?

The radius in meters of a 1.0cm tube is 0.005m, right?

So I do (7.0)x(pi)x(0.005^2) and I keep getting 5.4977 x 10^-4. But when I enter the amount in (online homework), it says that it is incorrect.

Answer 1

that should be right

Answer 2

You have a rounding error.  The value is actually 5.4978E-4 (actually 5.497787144E-4).  Did the online program give you a required precision?  Perhaps you're entering too many or two few digits.  (Technically, since the lowest precision value you have is 7.0 m/s (1 digit precision), your answer should be expressed to that same precision: 5.5E-4 m^3/s.

Answer 3

There is one thing missing. There is such a thing as coefficient of discharge. Hence the equation flow rate is:

Q = cAV

Where:

Q = volume flow rate

c= coefficient of discharge usually equal to 0.8

A = area of the tube

V = velocity of discharge