Q2 · 2023 · Paper 2Complex unfamiliar5 marks
QUESTION 2 (5 marks)
In a frictionless system, object A rests on an inclined plane and object B undergoes horizontal circular motion. The two objects are connected by a length of string as shown.
Determine the speed of object B needed for object A to remain stationary. Show your working.
WORKED SOLUTION
5 marksQCAA guide · typeset solution
ANSWER
See worked solution below.
Worked solution
For object A to remain stationary, the parallel component of force due to gravity equals the tension, and the tension provides the centripetal force on object B. The calculation gives a speed of 1.7 m s⁻¹.
• identifies the equivalence of the parallel component of force due to gravity and centripetal force [1 mark]
• calculates the parallel component of force due to gravity [1 mark]
• recognises the scenario relates to centripetal force acting on an object [1 mark]
• provides appropriate mathematical reasoning [1 mark]
• calculates the speed of object B [1 mark]
One QCAA sample method typeset for web; criterion wording is adapted from the official marking guide.
How many marks did you earn?
Compare your working with the guide above.