FCTC Mechanical Reasoning Principles Questions and Answers 5

Question 1

A centrifugal pump's impeller speed is doubled. By approximately what factor does the pump's flow rate change?

Accepted Answer

2×

Answer

By the centrifugal pump affinity laws, flow rate is directly proportional to impeller speed.

Question 2

Which material would be the best thermal insulator in a mechanical system?

Accepted Answer

Fiberglass

Answer

Fiberglass has very low thermal conductivity, making it an excellent insulator compared to metals.

Question 3

A shaft transmits 10 hp at 1,000 RPM. If the speed is reduced to 500 RPM while maintaining the same power, the torque will:

Accepted Answer

Double

Answer

Power = Torque × Speed; if speed halves and power stays constant, torque must double.

Question 4

A pipe joint leaks when pressure increases. The most likely cause is:

Accepted Answer

A failed or worn gasket

Answer

Gaskets create the seal between pipe flanges; a worn or damaged gasket will fail under increased pressure.

Question 5

In a simple electrical circuit, if the resistance is doubled while voltage stays the same, the current will:

Accepted Answer

Be halved

Answer

By Ohm's Law, I = V/R; if R doubles and V is constant, current (I) is cut in half.

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