Question

For your sink at home, the flow rate in is 5000 units/hr. Accumulation is 2500 units. What is the accumulation rate if the out flow is 60 units/min? multiple choice

a) 2400 units/hr b) 400 units/hr c)100 units/hr d) 1400 units/hr e) 3400 units/hr

f) other ____________________

Answer 1

Answer:

• Option d) 1400 units/hr

Explanation:

Using law of conservation of mass, you can do a mass balance or volume balance:

• Volume in - Volume out = Volume accumulation

If you divide by time unit, you get flow balance:

• Volume in / time - Volume out / time = Volume accumulation / time

• Flow rate in - Flow rate out =  Accumulation rate

Here you have:

• Flow rate in = 5000 units/h

• Flow rate out = 60 units/min

        Convert to rate in units/h: (60 units /min) × (60 min/h) = 3600 units/h

        Flow rate out = 3600 units/h

Then:

• Accumulation rate = 5000 units/h - 3600 units/h = 1400 units/h