This question is about pressure - Edexcel - GCSE Physics - Question 4 - 2023 - Paper 2
Question 4
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 aero... show full transcript
Worked Solution & Example Answer:This question is about pressure - Edexcel - GCSE Physics - Question 4 - 2023 - Paper 2
Step 1
Calculate the pressure difference inside and outside of the aeroplane.
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Answer
To find the pressure difference, we subtract the external atmospheric pressure from the internal cabin pressure:
Calculate the size of the force on the window due to the cabin air pressure of 80 000 Pa.
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Answer
We use the formula for pressure:
P=AF
Rearranging gives:
F=PimesA
Substituting in the values:
F=80000extPa×0.094extm2=7520extN
Step 3
Explain how the force due to the air pressure inside the cabin on the small window differs from the force on the larger window.
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The force on a window due to air pressure is calculated with the same pressure exerted. However, because the area of the smaller window is less than that of the larger window, the total force on the smaller window will be less. Thus, while the pressure remains the same, the force is proportional to the area of the window.
Step 4
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.
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An arrow should be drawn pointing inwards towards the inside of the aeroplane at point X, indicating that the resultant force acts towards the cabin due to higher pressure inside compared to outside.
Step 5
Describe how the atmospheric pressure changes with height above the Earth’s surface.
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Atmospheric pressure decreases as height increases. This is evidenced by the graph in Figure 7, which shows that with an increase in height from 0 to 25,000 m, the atmospheric pressure drops from 120 kPa to values significantly lower, reflecting a non-linear relationship. At 5,000 m, for example, the pressure has decreased significantly.
Step 6
Suggest one reason why the atmospheric pressure changes with height above the Earth’s surface.
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One reason is that as height increases, the air becomes less dense. The particles of air are more spread out at higher altitudes, leading to a decrease in atmospheric pressure.
