An airline passenger wants to check the weight of a suitcase he is carrying as hand luggage on to an aeroplane. He balances a uniform wooden plank, pivoted at its centre, as shown in Fig. 2.1. The plank is in equilibrium with the suitcase on one side of the pivot and three bags of sugar, each with mass $2.0\,\text{kg}$, on the opposite side. The distances are shown in Fig. 2.1.
(a)[2]
State the principle of moments.
(b(i))[1]
Calculate the weight of one bag of sugar.
(b(ii))[2]
The greatest permitted weight for a suitcase that can be taken on to the aeroplane is $67\,\text{N}$. Determine whether the suitcase weight is greater than the maximum allowed. Show a calculation in your answer.
(c(i))[1]
State what is meant by the ‘centre of gravity’ of an object.
(c(ii))[2]
When the slope is made very steep, the bus topples by rotating about point P. Explain why the bus falls over.
Worked solution & mark scheme
This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Clockwise moments = anticlockwise moments” …