Figure 16 shows a metal container with a movable piston - Edexcel - GCSE Physics - Question 7 - 2020 - Paper 1
Question 7
Figure 16 shows a metal container with a movable piston.
Point X is on the inner surface of the container.
The gas in the container is at a higher pressure than th... show full transcript
Worked Solution & Example Answer:Figure 16 shows a metal container with a movable piston - Edexcel - GCSE Physics - Question 7 - 2020 - Paper 1
Step 1
Which of these shows the direction of the force, due to the gas, on the container at point X?
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Answer
The correct answer is option C, as the force due to the gas on the container at point X is directed outward, indicating pressure exerting force on the container walls.
Step 2
Calculate the new pressure of the gas, P₂:
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Answer
To find the new pressure P₂ when the volume changes, we use the formula: P2=V2P1×V1
Given:
P₁ = 120 , \text{kPa}
V₁ = 2500 , \text{cm}³
V₂ = 1600 , \text{cm}³
Now substituting the values: P2=1600 cm3120 kPa×2500 cm3 P2=1600300000=187.5 kPa
So, the new pressure P₂ is 187.5 kPa.
Step 3
Calculate the pressure, in N/cm², of the piston on the air in the bicycle pump.
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Answer
We know that pressure is defined as: P=AF
where F is the force applied and A is the area of the piston.
Given:
F = 28 N and A = 2 cm², substituting these values: P=2 cm228 N=14N/cm2
Thus, the pressure of the piston on the air is 14 N/cm².
Step 4
Explain, in terms of the movement of particles, why there is a pressure on the container and why the pressure changes as shown in Figure 18.
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Answer
The pressure inside the container is generated by gas particles that are in constant motion. As these particles collide with the walls of the container, they exert a force, resulting in pressure. In Figure 18, as the volume of the gas increases, the distance between the particles also increases, leading to fewer collisions against the container walls, which results in a decrease in pressure. Conversely, when the volume decreases, particles are more densely packed, leading to more frequent collisions and thus higher pressure. This illustrates the inverse relationship between volume and pressure, known as Boyle's Law.
