Calculating the Mass Flow Rate for Point C

[jimbo71]

Homework Statement

see attachment

Homework Equations

Av=dV/dt
mass flow rate =roe*dV/dt

The Attempt at a Solution

the velocity at point c is 50m/s and the area of the opening is 0.04m^2. (50m/s)(0.04m^2)(1000kg/m^3)=2000Kg/s

 

[Carid]

Do you think these questions sometimes give you extra information in order for you to show that you know how to sort out the essential from the not useful?
At point B the pipe is wider than at C.
At B will the water be flowing faster, slower, or the same speed as a point C ?
Obviously the same amount of water must pass point B and point C.
So what can we say about the mass flow at B?

 

[stewartcs]

Homework Statement

see attachment

Homework Equations

Av=dV/dt
mass flow rate =roe*dV/dt

The Attempt at a Solution

the velocity at point c is 50m/s and the area of the opening is 0.04m^2. (50m/s)(0.04m^2)(1000kg/m^3)=2000Kg/s

Looks correct to me.

CS

 

[Carid]

Stewart,
Yes he's right, but the question gives a lot of unnecessary detail and I was trying to see if he was misled by it.

 

[jimbo71]

I was a little mislead by the simplicity of the problem. Since the 6th grade, I've known some problems give more information than needed.

 

[stewartcs]

Stewart,
Yes he's right, but the question gives a lot of unnecessary detail and I was trying to see if he was misled by it.

Typically when students give the correct answer it implies that they were not mislead by it!

CS