Q23 · 2020 · Paper 1Simple familiar2 marks
QUESTION 23 (2 marks)
Twin astronauts conduct an experiment where one travels with a velocity close to the speed of light to a distant planet, while the other stays on Earth. Each twin expects the other to be a different age by the time the first twin reaches and remains on the distant planet. Use the theory of special relativity to explain why the twins will no longer be the same age, and draw a conclusion about which twin will be younger.
WORKED SOLUTION
2 marksQCAA guide · typeset solution
ANSWER
See worked solution below.
Worked solution
The theory of special relativity states that there is no
absolute time. Instead, the measurement of time is
relative to the frame of reference in which it is
measured. The time measured by a stationary clock
is greater than the time measured by a moving clock.
From the perspective of either twin, the other twin will
be younger.
• provides an explanation of why the twins will no longer
be the same age
• supports the explanation using the theory of special
relativity
• provides a conclusion about the respective ages of the
twins that indicates an understanding of the twin paradox
2
• provides an explanation of why the twins will no longer
be the same age
• supports the explanation using the theory of special
relativity
OR
• provides an explanation of why the twins will no longer
be the same age
• provides a conclusion about the respective ages of the
twins that indicates an understanding of special relativity
1
One QCAA sample method typeset for web; criterion wording is adapted from the official marking guide.
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