p.6
Pressure Calculation Examples
If a force of 20 N is applied on piston A with an area of 10 cm², what is the pressure exerted?
20,000 N/m² (or 2 N/cm²).
p.21
Hydrometers and Density Measurement
What is the purpose of a hydrometer?
To measure the density of liquids and solutions.
p.16
Practical Experiments Demonstrating Pressure Concepts
What are the different stages of submerging the metal cube?
Near the water surface, half submerged, fully immersed near the surface, and fully immersed far from the surface.
p.16
Practical Experiments Demonstrating Pressure Concepts
What is the first step in Activity 15.4?
Get a cubic shaped piece of metal and mark where its volume is divided into two equal parts.
p.8
Applications of Hydraulic Systems
What components are involved in the vehicle's brake system?
Master cylinder, slave cylinder, brake pads, and brake discs or drums.
p.11
Atmospheric Pressure Measurement
What is the purpose of a mercury barometer?
To measure atmospheric pressure.
p.4
Hydrostatic Pressure Characteristics
What factors does liquid pressure depend on?
Liquid pressure depends on the vertical height of the liquid column and not on the shape or amount of liquid.
p.4
Hydrostatic Pressure Characteristics
What does the experiment in Activity 15.1 demonstrate about liquid pressure?
It shows that the pressure at equal levels of a liquid is the same, regardless of the shape of the liquid column.
p.6
Pressure Calculation Examples
What is the formula to calculate pressure in a liquid?
Pressure = h ρ g, where h is depth, ρ is density, and g is acceleration due to gravity.
p.1
Definition of Pressure
Who is the unit of pressure named after?
French scientist Blaise Pascal.
p.1
Definition of Pressure
What is the unit of pressure?
Newtons per square meter (Nm²), also known as Pascal (Pa).
p.15
Transmission of Pressure in Liquids
What happens to the spring balance reading when a downward force is exerted on a piece of metal?
The spring balance reading increases.
p.13
Transmission of Pressure in Liquids
What is the siphon method used for?
To draw water from a tank situated at a higher level to a tank at a lower level.
p.12
Atmospheric Pressure Measurement
How does an aneroid barometer work?
The shape of the cavity walls varies with external pressure, causing an attached indicator to rotate.
p.16
Practical Experiments Demonstrating Pressure Concepts
What is the purpose of submerging the metal cube in water?
To record the spring balance readings and the weight of the beaker with displaced water.
p.10
Atmospheric Pressure Measurement
Who first measured atmospheric pressure and what instrument did he use?
The Italian scientist Torricelli used a barometer.
p.11
Atmospheric Pressure Measurement
What happens to the mercury column when the barometer tube is turned upside down?
The mercury column drops, leaving an empty space above it.
p.15
Transmission of Pressure in Liquids
What occurs to the spring balance reading when an upward force is applied to the piece of metal?
The spring balance reading decreases.
p.10
Transmission of Pressure in Liquids
What occurs when the knot on the air-filled balloon connected to arm X is undone?
The water level in arm X goes down while the water level in arm Y goes up.
p.13
Transmission of Pressure in Liquids
What happens when the finger is removed from the siphon tube?
Water starts to flow from tank A to tank B.
p.18
Factors Affecting Floatation
What is the state of object B in water?
Fully submerged and floating.
p.18
Practical Experiments Demonstrating Pressure Concepts
What materials are needed for the activity?
Three objects of different materials, one of which should float partially submerged, another fully submerged, and one that sinks.
p.10
Transmission of Pressure in Liquids
Why do the water levels in the U-tube change when the balloon is connected?
The pressure in arm X at the liquid surface is higher due to the additional pressure exerted by the compressed air in the balloon.
p.13
Transmission of Pressure in Liquids
What determines the pressure at the end of the tube in tank A?
The sum of the pressures due to the water column in tank A and the atmospheric pressure.
p.3
Hydrostatic Pressure Characteristics
What happens when you make holes at the same level near the bottom of a filled plastic bottle?
Water exits the bottle, and the horizontal distance traveled by water from each hole is the same.
p.21
Archimedes' Principle
How does a hydrometer work according to Archimedes' principle?
It displaces a weight of liquid equal to its own weight.
p.13
Transmission of Pressure in Liquids
What is necessary for a rubber sucker to function properly?
There must be no air flow between the edge of the sucker and the glass surface.
p.8
Transmission of Pressure in Liquids
What principle is applied in a hydraulic jack?
The principle of liquid pressure transmission.
p.15
Transmission of Pressure in Liquids
What is observed when the object is immersed in water?
The spring balance reading decreases.
p.18
Practical Experiments Demonstrating Pressure Concepts
How can object B be created for the experiment?
By filling a bottle with an appropriate quantity of sand and closing it properly.
p.11
Atmospheric Pressure Measurement
What does the height of the mercury column represent?
A measure of atmospheric pressure.
p.20
Archimedes' Principle
What can be concluded about the weight and upthrust of partially submerged and floating objects?
The weight is equal to the upthrust exerted on the objects by water.
p.12
Atmospheric Pressure Measurement
How does atmospheric pressure change with altitude?
It decreases as we move up from sea level.
p.12
Atmospheric Pressure Measurement
What is an aneroid barometer?
A barometer that does not contain liquid and measures pressure using a cavity with evacuated air.
p.4
Hydrostatic Pressure Characteristics
In what directions is the pressure the same at a given point in a liquid?
The pressure is the same in all directions.
p.8
Transmission of Pressure in Liquids
What happens to the pressure in the brake system after it is created in the master cylinder?
The pressure is transmitted through the oil to the slave cylinder near the wheel.
p.13
Transmission of Pressure in Liquids
What must be done to the siphon tube before it can be used?
The tube must be filled with water and one end pressed with a finger.
p.21
Factors Affecting Floatation
What happens when the upthrust on an object is greater than its weight?
The object floats while partially submerged in the fluid.
p.6
Applications of Hydraulic Systems
What are the areas of pistons A and B in the hydraulic press example?
Piston A: 10 cm², Piston B: 200 cm².
p.7
Transmission of Pressure in Liquids
What total force is exerted on a piston B with an area of 200 cm²?
400 N (2 N/cm² x 200 cm²).
p.20
Archimedes' Principle
What happens to an object that sinks in water?
Its weight is greater than the upthrust exerted on it by water.
p.2
Hydrostatic Pressure Characteristics
How does pressure exerted by a solid object on a table work?
The force due to the weight of the object spreads over the total contact area.
p.20
Archimedes' Principle
What are the conditions for an object to float or sink in a fluid?
(a) If upthrust is less than weight, the object sinks; (b) If upthrust equals weight, the object floats.
p.4
Hydrostatic Pressure Characteristics
How does liquid pressure behave at the same level in a liquid?
The pressure is the same at the same level of a liquid.
p.18
Factors Affecting Floatation
What is the state of object C in water?
Fully submerged and resting at the bottom.
p.6
Transmission of Pressure in Liquids
What principle allows pressure to be transmitted through liquids?
Liquids do not get compressed by forces exerted on them.
p.15
Archimedes' Principle
What does the activity demonstrate about forces acting on an object in a fluid?
A downward force increases the reading, while an upward force decreases it, confirming the presence of buoyant force.
p.13
Transmission of Pressure in Liquids
Why does water flow from tank A to tank B in the siphon method?
Because the pressure in tank A is higher than in tank B, which is exposed to atmospheric pressure.
p.5
Pressure Calculation Examples
What is the formula for calculating the weight of a liquid column above a unit area?
Weight = hρg, where h is the height, ρ is the density, and g is the acceleration due to gravity.
p.18
Factors Affecting Floatation
What is the state of object A in water?
Partially submerged and floating.
p.11
Atmospheric Pressure Measurement
Why does the mercury in the tube not flow down completely into the container?
Because atmospheric pressure pushes on the mercury surface exposed to the outside.
p.15
Archimedes' Principle
What does the decrease in spring balance reading when the object is immersed in water indicate?
It indicates that the object experiences an upward thrust exerted by the liquid.
p.12
Applications of Hydraulic Systems
How does drinking with a straw demonstrate atmospheric pressure?
Sucking air out of the straw reduces pressure inside, allowing atmospheric pressure to push liquid up the straw.
p.9
Definition of Pressure
What does it mean when it is stated that 'the pressure is 1500 Pa'?
It refers to the pressure exerted at the bottom of a container due to the liquid inside it.
p.11
Atmospheric Pressure Measurement
What happens to the height of the mercury column if the tube is immersed further into the mercury container?
The height remains at 76 cm, but the space above the column reduces.
p.17
Archimedes' Principle
What does the spring balance reading indicate in the experiment?
It indicates the weight of the metal cube in different stages of submersion.
p.20
Transmission of Pressure in Liquids
What happens when the external force on object A is removed?
The object returns to the position where upthrust equals its weight.
p.7
Applications of Hydraulic Systems
Why is a compressor used in actual hoists instead of a small piston?
To pump oil into the small cylinder, making it easier to lift vehicles.
p.22
Pressure Calculation Examples
What is the force exerted by water on an area of 200 cm² at the bottom of the reservoir?
Force = 12000 Pascals × 0.02 m² = 240 N.
p.19
Archimedes' Principle
What conclusion can be drawn from the results regarding Object A?
Object A is floating due to its weight being less than the upthrust.
p.8
Transmission of Pressure in Liquids
How is pressure transmitted in a vehicle's brake system?
When the driver applies force on the brake pedal, it is transmitted to the piston in the master cylinder, creating pressure in the oil.
p.10
Transmission of Pressure in Liquids
What happens to the water levels in a U-tube when water is poured into it?
The water levels in the two arms X and Y become equal.
p.16
Practical Experiments Demonstrating Pressure Concepts
What should be measured after weighing the metal cube?
The weight of the beaker.
p.20
Transmission of Pressure in Liquids
What occurs when an external force is applied to object A?
An additional upward force can be experienced due to greater upthrust than weight.
p.19
Archimedes' Principle
How is Object B positioned in water?
Fully submerged and floating.
p.14
Archimedes' Principle
Does upthrust only occur in water?
No, any fluid exerts upthrust on immersed objects.
p.22
Practical Experiments Demonstrating Pressure Concepts
How can you determine if the pressure inside a balloon is less than or greater than atmospheric pressure?
Use a pressure gauge to measure the pressure inside the balloon and compare it to atmospheric pressure.
p.4
Hydrostatic Pressure Characteristics
What is the relationship between the height of a liquid column and liquid pressure?
The pressure at a certain point in a liquid increases with the height of the liquid column above that point.
p.18
Practical Experiments Demonstrating Pressure Concepts
What activity is suggested to understand the differences in buoyancy?
Measure the weights and apparent weights of three objects in water.
p.14
Pressure Calculation Examples
How do you calculate atmospheric pressure in Pascals using mercury?
P = h × ρ × g, where h = 76/100 m, ρ = 13600 kg/m³, g = 10 m/s².
p.3
Hydrostatic Pressure Characteristics
What does the experiment with holes at different heights in a water-filled bottle demonstrate?
The speed of water streams increases as the depth of the hole increases, indicating that pressure in a liquid increases with depth.
p.9
Pressure Calculation Examples
What is the pressure caused by water at the bottom of a pond with a depth of 1.5 m?
Pressure = depth × density × gravity = 1.5 m × 1000 kg/m³ × 9.81 m/s².
p.9
Pressure Calculation Examples
How do you calculate the pressure exerted by sea water at a depth of 1 km?
Use the formula: Pressure = depth × density × gravity = 1000 m × 1050 kg/m³ × 9.81 m/s².
p.3
Hydrostatic Pressure Characteristics
What is the relationship between the speed of water exiting a hole and the pressure near that hole?
Water exiting a hole has a higher speed when the pressure near that hole is higher.
p.22
Practical Experiments Demonstrating Pressure Concepts
Describe a simple experiment to demonstrate that pressure in a liquid increases with depth.
Use a clear container filled with water and multiple holes at different depths; observe that water sprays farther from lower holes.
p.22
Archimedes' Principle
What is the weight of the water displaced by a piece of metal when it is completely immersed in water?
Weight of water displaced = Upward thrust = 15 N.
p.1
Definition of Pressure
What does it mean that pressure is a scalar quantity?
It means pressure has only magnitude and no direction.
p.8
Transmission of Pressure in Liquids
Why is the force applied on the brake pads greater than the force applied by the driver?
Because the cross-sectional area of the slave cylinder is larger than that of the master cylinder.
p.10
Atmospheric Pressure Measurement
What is atmospheric pressure?
The pressure at any point in the atmosphere due to the weight of the air above that point.
p.5
Pressure Calculation Examples
How is the mass of the liquid column calculated?
Mass = density × volume = ρ × area of its base × height = ρ × 1 × h = hρ.
p.22
Pressure Calculation Examples
What is the pressure at the bottom of a reservoir with a depth of 1.2 m?
Pressure = 1.2 m × 1000 kg/m³ × 10 m/s² = 12000 Pascals.
p.17
Archimedes' Principle
What happens to the upthrust when the metal cube is half submerged in water?
The upthrust is 0.3 N, equal to the weight of the displaced water.
p.9
Atmospheric Pressure Measurement
What is atmospheric pressure?
It is the pressure produced by the weight of a column of air above a given point.
p.22
Archimedes' Principle
What is the upward thrust exerted on a piece of metal weighing 20 N when its apparent weight in water is 5 N?
Upward thrust = Weight in air - Apparent weight in water = 20 N - 5 N = 15 N.
p.9
Pressure Calculation Examples
What is the pressure exerted by a mercury column of height 10 cm?
To calculate, use the formula: Pressure = height × density × gravity. For mercury, it would be 0.1 m × 13600 kg/m³ × 9.81 m/s².
p.21
Hydrometers and Density Measurement
What does the scale on a hydrometer indicate?
The density of the liquid or solution being measured.
p.5
Pressure Calculation Examples
Calculate the pressure exerted by water at a depth of 1.5 m in a lake.
Pressure = hρg = 1.5 m × 1000 kg m⁻³ × 10 m s⁻² = 15,000 Pa.
p.22
Archimedes' Principle
What is Archimedes' principle?
A body immersed in a fluid experiences an upward thrust equal to the weight of the fluid displaced.
p.7
Transmission of Pressure in Liquids
How is a force of 400 N transmitted from a smaller piston to a larger piston?
Through the transmission of pressure in the liquid.
p.3
Hydrostatic Pressure Characteristics
How does the height of the water column in a vessel affect the pressure?
The pressure increases with the height of the liquid column.
p.22
Pressure Calculation Examples
What is the formula to calculate pressure at the bottom of a reservoir?
Pressure = depth × density × gravitational acceleration.
p.21
Factors Affecting Floatation
What determines how deep a hydrometer is immersed in a liquid?
The density of the liquid; higher density liquids require less immersion.
p.5
Pressure Calculation Examples
What units are used for height (h), density (ρ), and acceleration due to gravity (g) in the pressure formula?
Height (h) in meters (m), density (ρ) in kg m⁻³, and g in m s⁻².
p.9
Transmission of Pressure in Liquids
How do gases exert pressure?
Gases exert pressure through the weight of a column of gas or when a compressed gas attempts to expand.
p.17
Archimedes' Principle
Who first introduced the principle that describes the relationship between upthrust and displaced fluid?
The scientist Archimedes.
p.21
Hydrometers and Density Measurement
What is the relationship between the volume of liquid displaced and the hydrometer?
The volume of liquid displaced is equal to the volume of the immersed part of the hydrometer.
p.19
Archimedes' Principle
What conclusion can be drawn from the results regarding Object B?
Object B is fully submerged and floating, indicating it displaces a volume of water equal to its weight.
p.10
Atmospheric Pressure Measurement
How does atmospheric pressure compare to pressure in a liquid container?
Similar to the pressure produced by water above a point in a container, atmospheric pressure exists due to the weight of air above that point.
p.17
Archimedes' Principle
What is the conclusion drawn from the experiment regarding upthrust and displaced water?
The upward thrust acting on the object is equal to the weight of the water displaced by the object.
p.14
Archimedes' Principle
How does water affect the weight of an object when it is immersed?
The weight felt in water is less than its weight in air due to upthrust.
p.19
Archimedes' Principle
What conclusion can be drawn from the results regarding Object C?
Object C is sunk, indicating its weight is greater than the upthrust.
p.13
Transmission of Pressure in Liquids
How does a rubber sucker adhere to a glass surface?
By creating a lower pressure inside the sucker compared to the atmospheric pressure outside.
p.9
Pressure Calculation Examples
What is the pressure at the bottom of a tank filled with a liquid of density 800 kg/m³?
Pressure = depth × density × gravity = 2 m × 800 kg/m³ × 9.81 m/s².
p.9
Pressure Calculation Examples
How do you calculate the force acting on the bottom of a tank due to pressure?
Force = Pressure × Area. Area = length × width.
p.22
Hydrostatic Pressure Characteristics
What is the height of a water column that exerts the same pressure as 76 cm Hg?
Height = Pressure / (density × g) = 101325 Pascals / (1000 kg/m³ × 9.81 m/s²) ≈ 10.3 m.
p.16
Practical Experiments Demonstrating Pressure Concepts
What should be recorded during the experiment?
Spring balance readings and the weight of the beaker with displaced water.
p.16
Practical Experiments Demonstrating Pressure Concepts
What conclusions can be drawn from the activity?
The relationship between the weight of the displaced water and the upthrust experienced by the submerged metal cube.
p.7
Applications of Hydraulic Systems
What is the role of the small piston in a hydraulic hoist?
To generate pressure in the oil that is transmitted to the large piston.
p.5
Atmospheric Pressure Measurement
What is the unit of pressure (P) exerted by the liquid column?
N m⁻², which is equivalent to Pascal (Pa).
p.7
Applications of Hydraulic Systems
What principle do hoists in service stations operate on?
The principle of pressure transmission through fluids.
p.3
Hydrostatic Pressure Characteristics
What can be concluded about pressure at the same level in a liquid?
The pressure at the same level of a liquid is the same.
p.2
Hydrostatic Pressure Characteristics
What happens to the pressure exerted by a liquid in a container?
It is exerted on the bottom and the vertical walls of the vessel.
p.17
Archimedes' Principle
What is the upthrust when the metal cube is fully immersed in water?
The upthrust is 0.6 N, equal to the weight of the displaced water.
p.22
Atmospheric Pressure Measurement
What is the atmospheric pressure at sea level in Pascals?
Atmospheric pressure = 76 cm Hg = 76 × 13,600 kg/m³ × 9.81 m/s² = 101325 Pascals.
p.17
Archimedes' Principle
What is Archimedes' Principle?
When an object is partially or completely submerged in a fluid, the upthrust acting on it is equal to the weight of the fluid displaced by the object.
p.2
Practical Experiments Demonstrating Pressure Concepts
What observation can be made when holes are made in a polythene bag filled with water?
Water exits through all the holes due to water pressure acting at each hole.
p.5
Hydrostatic Pressure Characteristics
What does the variable 'h' represent in the pressure formula?
'h' represents the height of the liquid column above the point in question.
p.17
Archimedes' Principle
What does the weight of the beaker with displaced water represent?
It represents the weight of the water displaced by the submerged object.
p.1
Pressure Calculation Examples
What is the formula for calculating pressure?
Pressure = Perpendicular force applied (F) / Area (A)
