Figure 14 shows the vertical forces on an aeroplane - Edexcel - GCSE Physics - Question 7 - 2018 - Paper 1
Question 7
Figure 14 shows the vertical forces on an aeroplane.
Use information from the diagram to determine the size and direction of the resultant vertical force on the aer... show full transcript
Worked Solution & Example Answer:Figure 14 shows the vertical forces on an aeroplane - Edexcel - GCSE Physics - Question 7 - 2018 - Paper 1
Step 1
Use information from the diagram to determine the size and direction of the resultant vertical force on the aeroplane.
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Answer
To determine the resultant vertical force, subtract the downward force (7.5 kN) from the upward force (8.4 kN).
Resultant Force = 8.4 kN - 7.5 kN = 0.9 kN.
The direction is upwards, as the upward force exceeds the downward force.
Step 2
Complete the diagram to show the resultant of these forces.
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Answer
In the diagram, draw a resultant vector that starts from the tail of the 300 N vector and ends at the tip of the 400 N vector, forming a right triangle.
Step 3
Calculate the change in gravitational potential energy of the aeroplane as it descends from 1300 m to the ground.
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Answer
The formula for gravitational potential energy (GPE) is given by:
GPE=mimesgimesh
Where:
m = mass of the aeroplane = 750 kg
g = gravitational field strength = 10 N/kg
h = height = 1300 m
Substituting in the values:
GPE=750imes10imes1300=9,750,000extJ
Step 4
Calculate the power output of the engine.
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Answer
To calculate the power output, we first determine the useful output energy:
extOutputEnergy=0.70imes6500extkJ=4550extkJ
Now to convert kJ to J, we have:
4450extkJ=4550000extJ
The time in minutes (1 minute = 60 seconds):
ext{Power} = 75833.33 ext{ W} = 75.83 ext{ kW}$$
Step 5
Explain why the efficiency of the engine is less than 1 (100%).
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Answer
The efficiency of the engine is less than 100% because not all input energy is converted into useful output energy. Some energy is lost during the process, primarily through heat, friction, and other forms of energy dissipation. This means only a portion of the total energy consumed contributes to the work performed by the engine.
