Question

A block of mass 2 kg is pushed against a rough vertical wall with a force of 40 N, coefficient of static friction being 0.5. Another horizontal force of 15 N, is applied on the block in a direction parallel to the wall. Will the block move? If yes, in which direction? If no, find the frictional force exerted by the wall on the block.

Answer 1

Net force on the block$=\sqrt{\left({20}^2+{15}^2\right)}-\left(0.5\right)\times 40$
= 25 − 20 = 5 N
$$\begin{gathered} \therefore \tan \mathrm{\theta }=\frac{20}{15}=\frac{4}{3} \\ \Rightarrow \theta ={\tan }^{-1}\left(\frac{4}{3}\right)=53° \end{gathered}$$
Therefore, the block will move at 53° angle with the 15 N force.