MCQ
A rough vertical board has an acceleration $‘a’$ so that a $2$ kg block pressing against it does not fall. The coefficient of friction between the block and the board should be
- ✓$ > g/a$
- B$ < g/a$
- C$ = g/a$
- D$ > a/g$
✓
Answer
Correct option: A.
$ > g/a$
a
(a) For the limiting condition upward friction force between board and block will balance the weight of the block.
(a) For the limiting condition upward friction force between board and block will balance the weight of the block.
i.e. $F > mg$
==> $\mu (R) > mg$
==> $\mu (ma) > mg$
==> $\mu > \frac{g}{a}$
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