Physics · LAWS OF MOTION

A block of mass \( m \) is pressed against a rough vertical wall by applying a horizontal force \( F \). If the coefficient of static friction between the wall and the block is \( \mu_s \), the minimum magnitude of horizontal force \( F \) required to prevent the block from slipping downwards is:

1. A
   \( \frac{mg}{1 + \mu_s} \)
2. B
   \( \mu_s mg \)
3. C
   \( \frac{\mu_s m}{g} \)
4. D
   \( \frac{mg}{\mu_s} \)