Atmospheric pressure

Figure 14 is a graph of atmospheric pressure against height above the surface of the Earth.

height above the surface of the Earth in m

Figure 14

The atmospheric pressure at 3000 m above the surface of the Earth, as shown in Figure 14, is

Use Figure 14 to describe how the atmospheric pressure depends on the height above the surface of the earth.

Figure 15 shows an oxygen cylinder used to provide patients with oxygen in hospital.

The volume of the cylinder, V₁, is 2.3 litres.

The pressure of gas in the cylinder, P₁, is 15 MPa.

Oxygen is released from the cylinder to the patient at a pressure of P₂ = 0.35 MPa.

Show that the total volume, V₂, of oxygen that can be released to the patient is about 100 litres at this pressure.

Use the equation

The oxygen from the cylinder flows to the patient at 6 litres / minute.

Calculate the time taken for the 100 litres of oxygen to be used up at this rate.

time taken_........ minutes

A patient requires oxygen for a longer period of time.

Suggest what could be done to supply oxygen over this longer period of time.

*(c) Figure 16 shows a cylinder containing some gas.

A piston prevents the gas escaping.

In Figure 16x a small weight pushes down and the volume and pressure of the gas are measured.

Following this, in Figure 16y, a larger weight pushes down and the volume and pressure of the gas are measured again.

small weight larger weight

Explain why the pressure and volume of the gas in the cylinder change when the larger weight pushes down on the piston. The temperature of the gas does not change.

Your answer should include

• how the volume and pressure change

• how the gas particles exert a force on the piston

Figure 25 shows an object at the bottom of a beaker of water.

Which diagram shows the direction of the force exerted by the water on the object at point X?

Figure 26 shows an ice skater standing on one skate.

Calculate the force the skate exerts on the ice.

pressure of skate on ice = 4.8 10 Pa⁷

area of blade in contact with ice = 1.2 10⁵ m²

Use the equation

force = pressure area

Give your answer to 2 significant figures.

force =_........

Figure 27 shows how atmospheric pressure changes with height above sea level.

Using the graph, describe how atmospheric pressure changes with height above sea level.

The top of Mount Everest is 8850 m above sea level. Using the graph, estimate the atmospheric pressure at the top of Mount Everest.

pressure =_........

On a different day, the pressure at sea level is 104 kPa and the pressure at a height of 2500 m is 74 kPa.

Calculate the percentage change in pressure from sea level to the height of 2500 m.

percentage change =_........

Figure 28 is a model representing molecules of the Earth’s atmosphere.

Use Figure 28 to explain how the density of the air varies with height above sea level.

Figure 9 shows an object at the bottom of a beaker of water.

Which diagram shows the direction of the force exerted by the water on the object at point X?

Figure 10 shows an ice skater standing on one skate.

Calculate the force the skate exerts on the ice

pressure of skate on ice = 4.8 10 Pa⁷

area of blade in contact with ice = 1.2 10⁵ m²

Use the equation

force = pressure area

Give your answer to 2 significant figures.

force =_........

Figure 11 shows how atmospheric pressure changes with height above sea level.

Using the graph, describe how atmospheric pressure changes with height above sea level.

The top of Mount Everest is 8850 m above sea level. Using the graph, estimate the atmospheric pressure at the top of Mount Everest.

pressure =_........

On a different day, the pressure at sea level is 104 kPa and the pressure at a height of 2500 m is 74 kPa.

Calculate the percentage change in pressure from sea level to the height of 2500 m.

percentage change =_........

Figure 12 is a model representing molecules of the Earth’s atmosphere.

Use Figure 12 to explain how the density of the air varies with height above sea level.

This question is about pressure.

Figure 22 shows windows in an aeroplane.

The aeroplane is high above the Earth’s surface.

The atmospheric pressure outside the aeroplane is 23 000 Pa.

The air pressure inside the aeroplane is 80 000 Pa.

Calculate the pressure difference between inside and outside of the aeroplane.

The surface area of the window is 0.094 m².

Calculate the size of the force on the window due to the cabin air pressure of 80 000 Pa.

Use the equation

On the same aeroplane, a different window has a smaller surface area.

Explain how the force due to the air pressure inside the cabin on the small window differs from the force on the larger window.

Figure 23 shows a cross‑section through the aeroplane including one window.

inside of aeroplane outside of aeroplane

Draw an arrow on Figure 23 to show the direction of the resultant force due to the air pressure inside the cabin on the window at point X.

Figure 24 shows the atmospheric pressure at different heights above the Earth’s surface.

height above the Earth’s surface in m

Figure 24

Describe how the atmospheric pressure changes with height above the Earth’s surface.

Use data from Figure 24 to support your answer.

Suggest one reason why the atmospheric pressure changes with height above the Earth’s surface.

Equations

This question is about pressure.

Figure 5 shows windows in an aeroplane.

The aeroplane is high above the Earth’s surface.

The atmospheric pressure outside the aeroplane is 23 000 Pa.

The air pressure inside the aeroplane is 80 000 Pa.

Calculate the pressure difference between inside and outside of the aeroplane.

The surface area of the window is 0.094 m².

Calculate the size of the force on the window due to the cabin air pressure of 80 000 Pa.

Use the equation

On the same aeroplane, a different window has a smaller surface area.

Explain how the force due to the air pressure inside the cabin on the small window differs from the force on the larger window.

Figure 6 shows a cross‑section through the aeroplane including one window.

inside of aeroplane outside of aeroplane

Draw an arrow on Figure 6 to show the direction of the resultant force due to the air pressure inside the cabin on the window at point X.

Figure 7 shows the atmospheric pressure at different heights above the Earth’s surface.

height above the Earth’s surface in m

Figure 7

Describe how the atmospheric pressure changes with height above the Earth’s surface.

Use data from Figure 7 to support your answer.

Suggest one reason why the atmospheric pressure changes with height above the Earth’s surface.

Figure 23 shows some water in a tank.

The bottom of the tank has an area of 0.80 m².

The force on the bottom of the tank, due to the water, is 2400 N.

Calculate the pressure, due to the water, on the bottom of the tank.

More water is added to the tank.

Explain how the pressure on the bottom of the tank changes when more water is added to the tank.

Figure 24 shows an object on the bottom of the tank of water.

Draw an arrow on Figure 24 to show the direction of the force exerted by the water on the surface of the object at point X.

Figure 25 is a graph showing how the atmospheric pressure changes with the height above sea level on the Earth’s surface.

height above sea level on the Earth’s surface in m

Figure 25

An aeroplane descends from 6000 m to 2000 m.

Use the graph to find the change in atmospheric pressure as the aeroplane descends.

change in pressure =_........

Suggest one reason why the atmospheric pressure is greater at 2000 m than at 6000 m.

Figure 26 shows two drawings of the same person on a bed.

Explain why the person exerts a different pressure on the bed when standing up than when lying down.

Figure 8 shows some water in a tank.

The bottom of the tank has an area of 0.80 m².

The force on the bottom of the tank, due to the water, is 2400 N.

Calculate the pressure, due to the water, on the bottom of the tank.

More water is added to the tank.

Explain how the pressure on the bottom of the tank changes when more water is added to the tank.

Figure 9 shows an object on the bottom of the tank of water.

Draw an arrow on Figure 9 to show the direction of the force exerted by the water on the surface of the object at point X.

Figure 10 is a graph showing how the atmospheric pressure changes with the height above sea level on the Earth’s surface.

height above sea level on the Earth’s surface in m

Figure 10

An aeroplane descends from 6000 m to 2000 m.

Use the graph to find the change in atmospheric pressure as the aeroplane descends.

Suggest one reason why the atmospheric pressure is greater at 2000 m than at 6000 m.

Figure 11 shows two drawings of the same person on a bed.

Explain why the person exerts a different pressure on the bed when standing up than when lying down.

Figure 1 shows an object under the surface of the sea.

Which arrow shows where the pressure on the object is greatest?

Figure 2 shows two blocks of stone resting on the bottom of the sea.

Both blocks have the same height.

Area Y is 4 times bigger than area X.

What is the pressure due to the water on the top surface of block Y?

A diver is swimming underwater in a lake.

The diver wears the meter shown in Figure 3.

The meter shows the depth of the diver below the surface of the water.

State the depth shown on the meter in Figure 3.

State the unit.

State how the pressure of the water on the diver changes as the diver swims down from the surface of the lake.

State why the total pressure on the diver is greater than just the pressure due to the water above the diver.

An aeroplane takes off from the ground.

State two factors that affect the pressure of the atmosphere on the aeroplane as the aeroplane goes higher in the atmosphere.

Figure 3 shows a diver swimming in a lake.

The pressure on the diver is due to both the water above him and the Earth’s atmosphere.

The pressure of air on the surface of the water is one atmosphere. 10 m of water is equivalent to one atmosphere.

How many atmospheres of pressure will be on the diver at a depth 20 m?

A balloon is filled with helium when it is on the ground.

The balloon is released and it rises through the atmosphere.

Explain what happens to the size of the balloon as it rises through the atmosphere.

Figure 4 shows a container of length 6.0 m and width 2.0 m resting on a floor. The weight of the container is 15 000 N.

Calculate the pressure that the container exerts on the floor.

Use the equation