Question

A wagon is accelerating to the right. A book is pressed against the back vertical side of the wagon. The coefficient of static friction between the book and the vertical back of the wagon is __________ μs.

Answer 1

Answer:

The coefficient of static friction between the book and the vertical back of the wagon is $\mu_{s} = mg/N$

Explanation:

Since the book is pressed against the vertical side of the wagon, the weight of the book will be acting downwards. i.e. $W_{b} = mg$

Let the frictional force between the book and the vertical back of the wagon be $f_{r}$

For the book not to drop down from the back vertical side of the wagon,

$f_{r} = mg$........................(1)

A static frictional force is given as $f_{r} = \mu_{s} N$............(2)

where N= Normal Reaction

Equating (1) and (2)

$mg = \mu_{s} N\\ \mu_{s} = mg/N$