Unit #5 Fluid Systems MC

Some banks use tubes to transport cylindrical canisters between the bank teller and the customer in the drive-through lane. Pressurized air propels the canister from the bank teller to the customer and back.

Which of the following best describes this system?

• a hydraulic system using liquids that can be compressed

• a hydraulic system using liquids that cannot be compressed

• a pneumatic system using gases that can be compressed

• a pneumatic system using gases that cannot be compressed

The diagram below shows a system of hydraulic pistons. The surface area of piston Y is nine times greater than the surface area of piston X. If a downward force of 10 N is applied to piston X, what upward force will piston Y exert?

• 3 N

• 10 N

• 30 N

• 90 N

An architect is designing a special fountain for an art museum. A system of copper pipes will be used to supply water to different parts of the fountain.

Which of the following will occur if the architect uses a 45° elbow instead of a 90° elbow in one section of the piping system?

• The water will stop flowing through the pipe, causing it to overflow.

• The water will flow with less resistance, allowing it to spray farther.

• The water will be blocked by air bubbles in the pipe, causing it to build up.

• The water will have more turbulent flow, decreasing the flow rate in the elbow.

Many mechanical systems are modeled after natural processes. Which human body function is most like a closed system?

• excreting sweat

• circulating blood

• breathing in oxygen

• secreting tears from ducts

An air compressor contains cooling coils that circulate water. Over time, these coils corrode and need to be cleaned in an acid bath to restore the efficiency of the system. A simplified diagram of this coil cleaning process is shown below.

Which of the following would convert the cleaning process from an open fluid system to a primarily closed fluid system?

• combining the fumes from the acid bath and the acid recovery tank

• transferring the acid from the acid bath directly to the waste containers

• moving the acid from the acid bath to the acid recovery tank at a slower rate

• pumping the acid from the acid recovery tank back into the acid storage tank

What do all pneumatic tools have in common?

• They are powered by water.

• They are powered by compressed gas.

• They are powered by recirculated fluid.

• They are powered by supercooled fluid.

A person is using a garden hose to water the plants in his yard. The hose does not have a nozzle. To make the water spray, the person covers part of the hose opening with his thumb, as shown below. The water will have the greatest velocity if the person leaves which percentage of the hose opening uncovered?

• 10%

• 25%

• 50%

• 80%

Hydraulic pistons are commonly used to hold a load in an exact position. Why might an air-driven piston be an inappropriate tool to use for this purpose?

• Air is invisible.

• Air is insulating

• Air is weightless.

• Air is compressible.

In the hydraulic system represented below, piston X has a cross-sectional area of 20 cm² and piston Y has a cross-sectional area of 10 cm². How far up will piston Y move if piston X is pushed down a distance of 2 cm?

• 1 cm

• 2 cm

• 4 cm

• 10 cm

Which of the following statements best describes open fluid systems?

• Water is the only fluid used in open systems.

• Fluids are not recirculated through open systems.

• Open systems are used only in hydraulic applications.

• Open systems require minimal energy for operation.