Moderate -0.3 This is a straightforward limiting equilibrium problem requiring resolution of forces in two perpendicular directions and application of F=μR. The setup is standard with clearly given values, requiring only routine application of mechanics principles with no conceptual challenges beyond basic A-level mechanics.
\includegraphics{figure_1}
A small ring \(P\) of mass \(0.03\) kg is threaded on a rough vertical rod. A light inextensible string is attached to the ring and is pulled upwards at an angle of \(15°\) to the horizontal. The tension in the string is \(2.5\) N (see diagram). The ring is in limiting equilibrium and on the point of sliding up the rod. Find the coefficient of friction between the ring and the rod. [4]
\includegraphics{figure_1}
A small ring $P$ of mass $0.03$ kg is threaded on a rough vertical rod. A light inextensible string is attached to the ring and is pulled upwards at an angle of $15°$ to the horizontal. The tension in the string is $2.5$ N (see diagram). The ring is in limiting equilibrium and on the point of sliding up the rod. Find the coefficient of friction between the ring and the rod. [4]
\hfill \mbox{\textit{CAIE M1 2019 Q1 [4]}}