(i)[5]
Show that $\mu \ge \frac{6}{17}$.
(ii)[3]
When the applied force acts upwards as in Fig. 2 the block slides along the floor. Find another inequality for $\mu$.
Mathematics 9709 · AS & A Level · Forces and equilibrium
Forces and equilibrium — practice question
A block of mass $2\,\text{kg}$ is initially at rest on a horizontal floor. The coefficient of friction between the block and the floor is $\mu$. A force of magnitude $12\,\text{N}$ is applied to the block at an angle $\alpha$ to the horizontal, where $\tan \alpha = \frac{3}{4}$. With the applied force directed downwards as in Fig. 1, the block stays at rest.