Question

A block of mass $m$ is placed on a rough horizontal surface whose coefficient of friction is $\mu$. An external horizontal force is applied to the block and its magnitude is gradually increased. The force exerted by the block on the surface is R.

• A. The magnitude of R will gradually increase
• B. $R\le mg\sqrt{{\mu }^2+1}$
• C. The angle made by R with the vertical will gradually increase
• D. The angle made by R with the vertical $\le {\tan }^{-1}\mu$

Answer 1

Answer: (A), (B), (C), (D)

The correct options are
A The magnitude of R will gradually increase
B $R\le mg\sqrt{{\mu }^2+1}$
C The angle made by R with the vertical will gradually increase
D The angle made by R with the vertical $\le {\tan }^{-1}\mu$