A-LevelMathematicsMechanics9709/42 · Oct/Nov 2024 · Q46 Marks

The diagram shows two particles, A and B, of masses 0.2kg and 0.1 kg respectively. The particles are suspended below a horizontal ceiling by two strings, AP and BQ, attached to fixed points P and Q on the ceiling. The particles are connected by a horizontal string, AB. Angle APQ = 45° and BQP = θ°. Each string is light and inextensible. The particles are in equilibrium. [Figure 4]

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Mark scheme

Marking points from the official mark scheme (Oct/Nov 2024). The mark or mark type is shown in brackets.

[*B1] BOD for using sin 45 instead of cos45, particularly if using wrong components in (b).
[DB1] Condone TAB =0.2g (with or without working) for full marks. WWW. DO NOT ISW.
[*M1] For resolving either horizontally OR vertically; 2 terms; allow sin/cos mix; allow their TAB; M0 for any use of TAB = TBQ = TAP.
[A1FT] For both. FT their TAB ONLY; TAB ≠ TBQ.
[DM1] Solve for θ or solve for TBQ from equations with the correct number of relevant terms. Using their TAB.
[A1] θ = 26.56505.... TBQ = 2.236067.... AWRT 26.6 and 2.24.

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