Filtered Air Is Pumped Down a Tube of Diameter 50

question 12

Multiple Choice

Filtered air is pumped down a tube of diameter 50 cm into a hospital operating theatre. The idea is that a laminar flow over the patient will prevent contamination. What is the maximum safe speed at which the air can be pumped which will ensure that the flow is not turbulent? The density of air is 1.2 kg m-3 and its viscosity is 1.8x10-5 Pa s.

• A) 1.2 cm s-1.
• B) 3.4 cm s-1.
• C) 6.9 cm s-1.
• D) 12.0 cm s-1.
• E) 23.4 cm s-1.ANS

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Definitions:

Time Deposits

A financial product provided by banks that offers a higher interest rate in exchange for keeping a specified amount of money untouched for a predetermined period.

Reserve Requirement

The minimum percentage of customer deposits and notes that a bank must hold as reserves rather than lending out, as mandated by the central bank.

Demand Deposits

Bank accounts from which deposited funds can be withdrawn at any time without any notice to the institution, typically through writing checks.

Excess Reserves

The reserves held by banks in excess of what is required by regulations, which can be loaned out to generate additional income.