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Physics · LAWS OF MOTION
हिन्दीA 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:
Correct answer · Option 4
\( \frac{mg}{\mu_s} \)
Explanation
Normal reaction \( N = F \). Vertical equilibrium requires static friction \( f_s = mg \). Since \( f_s \le \mu_s N \Rightarrow mg \le \mu_s F \Rightarrow F \ge \frac{mg}{\mu_s} \).
