3
\includegraphics[max width=\textwidth, alt={}, center]{af19f1e0-4cdf-407b-a0d6-cb0272066c30-2_492_606_1763_772}
Forces of magnitudes \(7 \mathrm {~N} , 10 \mathrm {~N}\) and 15 N act on a particle in the directions shown in the diagram.
- Find the component of the resultant of the three forces
(a) in the \(x\)-direction,
(b) in the \(y\)-direction. - Hence find the direction of the resultant.
\includegraphics[max width=\textwidth, alt={}, center]{af19f1e0-4cdf-407b-a0d6-cb0272066c30-3_414_833_267_657}
A block of mass 8 kg is at rest on a plane inclined at \(20 ^ { \circ }\) to the horizontal. The block is connected to a vertical wall at the top of the plane by a string. The string is taut and parallel to a line of greatest slope of the plane (see diagram). - Given that the tension in the string is 13 N , find the frictional and normal components of the force exerted on the block by the plane.
The string is cut; the block remains at rest, but is on the point of slipping down the plane.
- Find the coefficient of friction between the block and the plane.