3 (a) (i) An aircraft starts from rest and accelerates along the runway for 36s to reach take-off velocity - Edexcel - GCSE Physics Combined Science - Question 3 - 2022 - Paper 1
Question 3
3 (a) (i) An aircraft starts from rest and accelerates along the runway for 36s to reach take-off velocity.
Take-off velocity for this aircraft is 82 m/s.
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Worked Solution & Example Answer:3 (a) (i) An aircraft starts from rest and accelerates along the runway for 36s to reach take-off velocity - Edexcel - GCSE Physics Combined Science - Question 3 - 2022 - Paper 1
Step 1
Show that the acceleration of the aircraft along the runway is about 2 m/s².
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Answer
To calculate the acceleration, we can use the formula for acceleration: a=tv−u
where:
v = final velocity (82 m/s),
u = initial velocity (0 m/s),
t = time (36 s).
Substituting the values: a=3682−0 a=3682 a≈2.28 m/s²
This rounds to approximately 2 m/s², confirming the calculation.
Step 2
Calculate the distance the aircraft travels along the runway before take-off.
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Answer
We can apply the equation of motion: v2=u2+2ax
Rearranging the formula to find distance (x): x=2av2−u2
Substituting the known values: x=2×2.28822−02
Calculating gives: x=4.566724≈1470.4extm
Thus, the aircraft travels approximately 1470.4 meters before take-off.
Step 3
Suggest one reason why the length of the runway used is always much longer than the calculated distance that the aircraft travels along the runway before take-off.
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One reason could be that real-life scenarios involve factors such as wind resistance and mechanical failures, which can affect the acceleration and distance requirements. Additionally, safety margins are included to ensure a safe take-off process.
Step 4
Calculate the kinetic energy of the aircraft as it lands.
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Answer
The formula for kinetic energy (KE) is: KE=21mv2
where:
m = mass of the aircraft (3.6 × 10² kg),
v = velocity (71 m/s).
Substituting the values into the equation: KE=21×3.6×102×712
Calculating gives: KE≈9.1×105 J
So, the kinetic energy of the aircraft as it lands is approximately 9.1 × 10⁵ joules.
Step 5
Give one way that the energy has been transferred to the surroundings.
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One way the energy has been transferred is through thermal dissipation due to air resistance and friction during landing.