Pneumatics_unit2_review

Which of the following statements is false?

• Absolute pressure is equal to the sum of the atmospheric pressure and

  the gauge pressure.

• Pressure is defined as the amount of force exerted multiplied by the

  area.

• A mercury barometer consists of a glass tube that is sealed at one end

  and open at the other.

• Flow rate describes the volume of fluid passing through the circuit per

  unit of time.

When a gas is compressed and its temperature remains constant, the

pressure of the gas

• decreases

• increases

• remains constant

• varies as the flow rate.

Needle valves are used to

• adjust flow rate in both directions.

• adjust flow rate in one direction only.

• adjust pressure in both directions.

• adjust pressure in one direction only.

Pressure drop across a needle valve refers to

• the maximum pressure in a branch circuit.

• the maximum pressure that the needle can withstand

• the difference between upstream and downstream pressures.

• the minimum pressure needed to create flow.

A check valve

• is manually opened and closed by an operator.

• is used only in industrial applications.

• is used to adjust a regulator or pressure reducing valve.

• allows fluid flow in one direction only.

What drives liquid up when you drink with a straw?

• The vacuum in your mouth

• The friction in the straw

• The atmospheric pressure pushing on the liquid surface

• None of those choices here.

What is the force exerted by a pressure of 140 kPa (20 psi) on

a 0.1 m² (150 in²) area?

• 14 x 10³ N (3000 lbf)

• 7 x 10³ N (1500 lbf)

• 1.4 x 10³ N (300 lbf)

• None of those choices here

The amount of lifting force generated by an air bearing is determined by

• the surface area of the air bearing and the pressure developed between

  the bearing and the work surface.

• the thickness of the bearing.

• the quantity of lubricant applied on the bearing

• None of the choices here.

A gas is initially at an absolute pressure of 400 kPa. What is its final absolute

pressure if its volume is doubled? Presume that the atmospheric pressure

is 101.3 kPa.

• 800 KPa

• 200 KPa

• 100 KPa

• None of the choices here.

When the air temperature (in K) in a fixed size receiver doubles,

• the volume doubles.

• the volume decreases by half.

• the pressure doubles.

• the pressure decreases by half.