Ans. to Q3 "B" P6 NOV 2002
1)Reset the clock to zero.
2)Remove the 50g brass from the boiling water by one hand and press the clock to start with the other hand.
3)After a certain period of time, place the brass into the cold water while pressing the clock to stop with the other hand to find the recorded time.
The correct answer is to use 50.3 cm mark as the centre, i.e move the pivot to the 50.3 cm mark.
Or, use polystyrene to add to the end to balance it at 50.0 cm exactly.