Q324 · Practice questionTechnology-freeComplex unfamiliar8 marks
QUESTION 324 (8 marks)
A small stage drone repeats a vertical routine metres, where is measured in seconds, for . A photograph is taken at a random time uniformly distributed on .
a)[2 marks]
Determine the maximum vertical speed of the drone.
b)[3 marks]
Determine exactly.
c)[3 marks]
Determine the exact height such that .
WORKED SOLUTION
8 marksPractice marking scheme
ANSWER
a) m/s. b) . c) m.
Worked solution
a) , so the maximum magnitude is m/s.
b) requires , so . Uniform probability is .
c) Set . The time above has length . Requiring this to be gives , so .
Exact answers unless rounding is specified; equivalent forms accepted.
a) Differentiates the height.
a) Gives the largest absolute rate.
b) Forms the sine inequality.
b) Finds the correct time interval.
b) Uses the uniform probability.
c) Expresses the time above H.
c) Equates the duration to 5% of the period.
c) Gives the exact height.
Practice question aligned to the current QCAA syllabus; review the worked solution and marking criteria.
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