Quiz Chapter 2: Pressure

1. A wooden block floats in water with 60% of its volume submerged. What is the density of the wood? (Density of water = 1000 kg m⁻³)

1. 600 kg m⁻³
2. 400 kg m⁻³
3. 1000 kg m⁻³
4. 1200 kg m⁻³

2. In a Venturi tube through which water flows horizontally, at which section is the fluid pressure the LOWEST?

1. At the widest section where speed is highest
2. At the narrowest constricted section where speed is highest
3. At the inlet section before any constriction
4. The pressure is uniform throughout the tube

3. A diver descends to a depth of 15 m in seawater of density 1025 kg m⁻³. What is the liquid pressure experienced by the diver due to seawater alone? (Take g = 9.81 m s⁻²)

1. 150,922 Pa
2. 252,222 Pa
3. 15,375 Pa
4. 100,562 Pa

4. An aerofoil wing creates lift because:

1. Air moves faster over the top surface, creating lower pressure above the wing than below it.
2. Air moves slower over the top surface, creating higher pressure above the wing than below it.
3. Air temperature is higher beneath the wing than above it.
4. The wing displaces air equal to its own total mass.

5. What happens to the atmospheric pressure as altitude above sea level increases?

1. Increases exponentially
2. Decreases because the air column above is shorter and air density decreases
3. Remains constant at 101 kPa
4. Decreases initially then rapidly increases in the stratosphere

6. A hydrometer is used to measure:

1. Atmospheric pressure at different altitudes
2. Gas pressure inside a sealed container
3. Relative density of liquids based on flotation depth
4. Flow velocity of liquids in pipes

7. An open U-tube manometer contains water (density = 1000 kg m⁻³). When connected to a gas supply, the water level on the open arm is 20 cm higher than the arm connected to the gas. Taking Patm = 101,000 Pa and g = 9.81 m s⁻², calculate the gas pressure.

1. 99,038 Pa
2. 102,962 Pa
3. 120,620 Pa
4. 101,962 Pa

8. If a hydraulic brake pedal force of 50 N produces a fluid pressure of 250 kPa, what is the area of the master cylinder piston?

1. 0.0002 m²
2. 0.005 m²
3. 5.0 m²
4. 0.20 m²

9. How does a submarine submerge deeper under water?

1. By pumping water out of its ballast tanks
2. By flooding its ballast tanks with sea water to increase total weight
3. By increasing the speed of its engine propeller
4. By reducing the overall density of the ballast air

10. A mercury barometer reads a height of 76 cmHg. What is this atmospheric pressure value in Pascals? (Density of mercury = 13,600 kg m⁻³, g = 9.81 m s⁻²)

1. 101,396 Pa
2. 76,000 Pa
3. 133,416 Pa
4. 10,140 Pa