Q23 · 2025 · Paper 1Simple familiar5 marks
QUESTION 23 (5 marks)
a)[1 mark]
Describe Kepler’s second law of planetary motion.
b)[4 marks]
The Earth’s mean orbital radius is , while Saturn’s mean orbital radius is .
Calculate the time taken in seconds for Saturn to complete one revolution around the Sun. Show your working.
WORKED SOLUTION
5 marksQCAA guide · typeset solution
ANSWER
See worked solution below.
Worked solution
a) Kepler’s second law states that a radius vector joining any planet to the Sun sweeps out equal areas in equal lengths of time.
b) Convert time from year to seconds:
Time taken =
describes Kepler’s second law of planetary motion
converts time
recognises that the scenario relates to Kepler’s third law
provides appropriate mathematical reasoning
calculates time taken for Saturn to orbit the Sun
One QCAA sample method typeset for web; criterion wording is adapted from the official marking guide.
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