A horizontal force of $10 \mathrm{~N}$ is necessary to just hold a block stationary against a wall. The…

A horizontal force of $10 \mathrm{~N}$ is necessary to just hold a block stationary against a wall. The co-efficient of friction between the block and the wall is $0.2$. The weight of the block is

1. $20 \mathrm{~N}$
2. $50 \mathrm{~N}$
3. $100 \mathrm{~N}$
4. $2 \mathrm{~N}$

Solution

$\mathrm{f}=\mathrm{mg} \Rightarrow \mu \mathrm{N}=\mathrm{W} \Rightarrow \mu .10=\mathrm{W}$ $\Rightarrow 0.2 \times 10=\mathrm{W}$ $\therefore \mathrm{W}=2 \mathrm{~N}$

Asked in: JEE Main 2003

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