May/June 2026 Paper 43

A block of mass $m\mathrm{kg}$ is pulled up a rough plane inclined at an angle of $30^{\circ }$ to the horizontal by a constant force of magnitude $20\mathrm{N}$. This force acts parallel to a line of greatest slope of the plane. The acceleration of the block is $2m/{\mathrm{s}}^2$. The coefficient of friction between the block and the plane is $0.4$. Find the value of $m$.