Standard +0.3 This is a straightforward equilibrium problem requiring Hooke's law (T = λx/l) and resolving forces. Students must recognize the string is stretched, calculate tension from friction force, then use the elastic string formula to find extension. It's a standard M2 exercise with clear setup and routine application of formulas, slightly easier than average due to single-step reasoning once the method is identified.
1
\includegraphics[max width=\textwidth, alt={}, center]{36259e2a-aa9b-4655-b0c2-891f96c3f5a4-2_549_775_269_685}
A particle \(A\) and a block \(B\) are attached to opposite ends of a light elastic string of natural length 2 m and modulus of elasticity 6 N . The block is at rest on a rough horizontal table. The string passes over a small smooth pulley \(P\) at the edge of the table, with the part \(B P\) of the string horizontal and of length 1.2 m . The frictional force acting on \(B\) is 1.5 N and the system is in equilibrium (see diagram). Find the distance \(P A\).
1\\
\includegraphics[max width=\textwidth, alt={}, center]{36259e2a-aa9b-4655-b0c2-891f96c3f5a4-2_549_775_269_685}
A particle $A$ and a block $B$ are attached to opposite ends of a light elastic string of natural length 2 m and modulus of elasticity 6 N . The block is at rest on a rough horizontal table. The string passes over a small smooth pulley $P$ at the edge of the table, with the part $B P$ of the string horizontal and of length 1.2 m . The frictional force acting on $B$ is 1.5 N and the system is in equilibrium (see diagram). Find the distance $P A$.
\hfill \mbox{\textit{CAIE M2 2008 Q1 [3]}}