A girl holds a book of mass $m$ against a vertical wall with a horizontal force $F$ using her finger, so that the book does not move. The frictional force on the book by the wall is
A girl holds a book of mass $m$ against a vertical wall with a horizontal force $F$ using her finger, so that the book does not move. The frictional force on the book by the wall is
- [KVPY 2012]
- A
$F$ and along the finger but pointing towards the girl
- B
$\mu F$ upwards, where $\mu$ is the coefficient of static friction
- C
$m g$ and upwards
- D
equal and opposite to the resultant of $F$ and $m g$
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- [AIIMS 1999]