Physics 5054 · O Level · Centre of gravity

Centre of gravity — practice question

The mass of a glass beaker is 50 g. A liquid with density $1.8\,\text{g cm}^{-3}$ is added to the beaker until the level reaches the $200\,\text{cm}^3$ mark.
(a)[3]

Calculate the combined mass of the beaker and what it contains.

(b(i))[1]

State what the term centre of mass means.

(b(ii))[3]

A metre rule rests on a pivot. The pivot tip is positioned beneath the 80 cm mark on the rule. The beaker and its contents are then moved to different positions along the rule until balance is achieved. Fig. 1.1 shows the setup when the rule is balanced. One edge of the beaker is at the 84 cm mark and the other edge is at the 92 cm mark. Calculate the mass of the rule.

Worked solution & mark scheme

This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: Use relation $m = \rho V$

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