Q17 · 2024 · Technology-freeComplex familiar6 marks
QUESTION 17 (6 marks)
The acceleration (m s) of an object that moves in a straight line in an easterly direction over time for seconds is given by , where is its velocity (m s).
The object is initially at rest at a position that is metres west of the origin.
A student uses this information to calculate that the object is positioned at the origin when seconds.
Evaluate the reasonableness of the student’s calculation.
WORKED SOLUTION
6 marksQCAA guide · typeset solution
ANSWER
The student’s calculation is reasonable.
Worked solution
Since ,
so . With , and . Therefore
Initially , giving . At ,
Thus the student’s calculation is reasonable.
correctly determines a general solution to the differential equation in terms of and time
determines an appropriate constant of integration
determines a general solution for displacement in terms of time
determines an appropriate constant of integration for displacement
determines a result for displacement when without a trigonometric term
provides an appropriate statement of reasonableness based on mathematical reasoning
One QCAA sample method typeset for web; criterion wording is adapted from the official marking guide.
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