A motorised scooter is travelling along a straight path with velocity $v \text{ m s}^{-1}$ over time $t$ seconds as shown by the following graph - AQA - A-Level Maths Mechanics - Question 14 - 2021 - Paper 2
Question 14
A motorised scooter is travelling along a straight path with velocity $v \text{ m s}^{-1}$ over time $t$ seconds as shown by the following graph.
Noosha says that, ... show full transcript
Worked Solution & Example Answer:A motorised scooter is travelling along a straight path with velocity $v \text{ m s}^{-1}$ over time $t$ seconds as shown by the following graph - AQA - A-Level Maths Mechanics - Question 14 - 2021 - Paper 2
Step 1
Determine the area under the curve between $12 \leq t \leq 36$
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Answer
To find the distance travelled by the scooter in the time interval from t=12 to t=36, we will calculate the area under the velocity curve using trapezoidal approximation. The area will be calculated as the sum of four trapezoids:
Trapezium 1: For the interval [12,20]:
Height 1 = 5.2
Height 2 = 6.2
Base length = 20−12=8
Area = rac{1}{2} (5.2 + 6.2) \times 8 = 44.8
Trapezium 2: For the interval [20,30]:
Height 1 = 6.2
Height 2 = 8.0
Base length = 30−20=10
Area = rac{1}{2} (6.2 + 8.0) \times 10 = 71.0
Trapezium 3: For the interval [30,36]:
Height 1 = 8.0
Height 2 = 6.0
Base length = 36−30=6
Area = rac{1}{2} (8.0 + 6.0) \times 6 = 42.0
Trapezium 4: For the interval [36,50] is not included in this interval.
Thus, the total area can be summed up as:
extTotalArea=44.8+71.0+42.0=157.8 m
Step 2
Compare the total area to Noosha's estimate
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Answer
Noosha estimated that the scooter travels approximately 130 metres during the time interval from 12≤t≤36.
From our calculation, the total area under the curve is 157.8 m, which is greater than her estimate. Therefore, we conclude: