Q3 · 2021 · Paper 2Simple familiar3 marks
QUESTION 3 (3 marks)
An object undergoes uniform circular motion in a path with a radius of r. Determine the effect on the radius if the mass of the object is doubled, but the centripetal force and velocity remain unchanged.
WORKED SOLUTION
3 marksQCAA guide · typeset solution
ANSWER
See worked solution below.
Worked solution
𝐹= 𝑚𝑣2
𝑟
Let R be the radius of the new path
𝑀𝑣2
𝑟
= 2𝑀𝑣2
𝑅
1
𝑟= 2
𝑅
𝑅= 2𝑟
The radius will double.
• recognises the scenario relates to uniform circular
motion [1 mark]
• provides correct reasoning [1 mark]
• indicates that the radius will double [1 mark]
One QCAA sample method typeset for web; criterion wording is adapted from the official marking guide.
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