How long will it take to fill a tank?

[ScienceGeek24]

Homework Statement

The water from a pipe flows into a tank of volume 180 m³. If the tank is initially empty, how long will it take to fill the tank?

Homework Equations

Q=vA

v1=12m/s
v2=22m/s
A2=0.180982 m²
A1=0.3318 m²

The Attempt at a Solution

This question is the third question from a 3 part problem. In the first two part they were asking me to find the velocity of position 2 of the pipe which is 22m/s, in the second part they were asking me for the diameter of position 2 in the pipe which is 48 cm and in this third part they are asking me how long does it take to fill in the tank with 180 m³.

My attempt was using volumetric flow, but which end should I use? v1a1 or v2a2 since they don't mention where is the tank located at.

any hints to where to start from?

 

[Villyer]

How does v1a1 compare to v2a2?

 

[ScienceGeek24]

Hmmm can you be more specific?

 

[Villyer]

You mentioned using the volume flow rate to find the answer, but is the volume flow rate at position one different than volume flow rate at position two?

 

[ScienceGeek24]

ah! so it really doesn't matter which end i use because they are both going to have the same volumetric flow?

 

[ScienceGeek24]

however, is volumteric flow correct to approach this problem?

 

[Villyer]

Exactly! All points along a point have the same volumetric flow, therefore you can choose any point you desire.And what is the equation and units for volumetric flow?

 

[ScienceGeek24]

Q=vA= (12 m/s)(0.3318 m2)= 3.98 m3 s-1

and the equation is Q=V/t?

 

[Villyer]

Q=vA= (12 m/s)(0.3318 m2)= 3.98 m3 s-1

and the equation is Q=V/t?

Right! Can Q=V/t be used to answer the question?

 

[ScienceGeek24]

yep just got it! 45.2 secs thanks!

 

[Villyer]

No problem, good luck with the rest of your physics.