Pressure and Buoyancy - JSS2 Basic technology Past Questions and Answers - page 2
Why does a hot air balloon rise?
The hot air inside is denser than the outside air
The hot air is less dense than the outside air
The balloon material repels gravity
The air inside the balloon is compressed
What happens to an object submerged in a fluid according to Archimedes' Principle?
It loses weight
It experiences an upward buoyant force
It dissolves
It gains mass
Which of the following best describes why a steel ship floats?
Steel is lighter than water
The shape of the ship
Steel expands in water
The ship is pushed up by magnetic forces
If an object's weight is equal to the buoyant force, the object will:
Sink
Float
Hover at the constant depth
Rise to the surface and then sink
In which unit is force measured that is used in the pressure formula?
Pascal
Joule
Newton
Watt
Define pressure and explain its units.
Pressure is the force per unit area applied perpendicular to a surface, represented as ( P = F / A ). Its SI unit is the Pascal (Pa), equivalent to one Newton per square metre (N/m²).
How does pressure affect the structural integrity of materials?
High pressure compresses materials, while low pressure allows expansion. Continuous high pressure can stress materials, potentially compromising their structural integrity. This is crucial in designing buildings and aircraft to withstand various pressure.
Explain Archimedes' Principle and its significance in understanding buoyancy.
Archimedes' Principle states that a submerged object experiences an upward buoyant force equal to the weight of the displaced fluid. It explains why objects float or sink based on their density relative to the fluid.
Describe the relationship between pressure and volume in the context of compression and expansion.
Pressure and volume are inversely proportional; increasing pressure compresses a gas, decreasing its volume, and vice versa. This principle is evident in compressed air storage, lung function during breathing, and aircraft cabin pressurisation.
How do hydrometers utilise the principles of buoyancy to measure the density of liquids?
Hydrometers measure liquid density using buoyancy, floating at different depths based on liquid density. The hydrometer sinks more in less dense liquids and less in denser ones, with a scale indicating density.