Figure 23 shows a drone - Edexcel - GCSE Physics - Question 9 - 2020 - Paper 1
Question 9
Figure 23 shows a drone.
The drone has four spinning blades.
The upward force produced enables the drone to rise in the air.
The speed at which the blades spin is m... show full transcript
Worked Solution & Example Answer:Figure 23 shows a drone - Edexcel - GCSE Physics - Question 9 - 2020 - Paper 1
Step 1
Describe the relationship between upward force and speed shown by this graph.
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Answer
The graph illustrates an increasing upward force as the speed of the drone's blades increases. Initially, at low speeds, the upward force is minimal, indicating that the drone struggles to gain lift. As the speed rises, the upward force increases significantly, suggesting enhanced lift capabilities. The relationship is non-linear, indicating that small increases in speed can lead to substantial increases in upward force.
Step 2
Calculate the change in gravitational potential energy when the drone rises through a height of 20 m.
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Answer
Using the formula for gravitational potential energy, we calculate:
extgpe=mimesgimesh
Substituting in the values,
extgpe=4.5extkgimes10extN/kgimes20extm=900extJ.
Step 3
State the amount of useful work done by the blades as the drone rises through 20 m.
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Answer
The amount of useful work done by the blades as the drone rises through 20 m is 900 J.
Step 4
Calculate the useful power developed by the blades in this time of 4 s.
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Answer
To find the useful power, we use the formula:
extpower=time takenwork done
Substituting the known values gives us:
power=4exts900extJ=225extW.
Step 5
Describe the changes in the way energy is stored when the drone rises from the ground.
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Answer
As the drone rises, energy transfer occurs from its electrical power source to mechanical energy within the drone’s blades. The electrical energy converted into mechanical energy propels the drone upward. Additionally, the gravitational potential energy is stored as the drone ascends, increasing with height. Therefore, the store of energy transitions from electrical to kinetic and gravitational as the drone rises.
