# Calculate discharge in L/s and Kg/s

## Homework Statement

A tank contains oil with a specific gravity of 0.80, which is discharged through a 30mm diameter pipe at 12m/s. Calculate the discharge in L/s and Kg/s.

## Homework Equations

specific gravity=density of oil/density of water
mass flow rate=volume flow rate*density
volume flow rate=velocity*area

## The Attempt at a Solution

Density=(0.8*1000)=800 kg/m^3
Area=pi(0.015)^2=7.068583471*10^-4
Q=12*7.068583471*10^-4=8.482300165*10^-3
m=8.482300165*10^-3*800=6.785840132 kg/s

Shouldn't L/s be the same since 1L=1Kg?

## Answers and Replies

Merlin3189
Homework Helper
Gold Member
Shouldn't L/s be the same since 1L=1Kg?
No. 1 L = 0.8 kg for this oil. Water has a density of 1 kg per litre. (All approximate.)

No. 1 L = 0.8 kg for this oil. Water has a density of 1 kg per litre. (All approximate.)
So the answer is 6.785840132 Kg/s and 8.482300165 L/s?

Merlin3189
Homework Helper
Gold Member
Yes.
But I would round these numbers to something sensible, like 2 sf. depending on the question's request. Since all the measurements are given to only 2 sf, you can hardly get a more accurate answer. If the question specifies that they are accurate to more figures, like RD = 0.8000 and pipe is 30.00mm and flow is 12.00 m/s even though these extra figures are not shown, then a more accurate answer would be appropriate.

• Parsifal1