# Friction help

• Nov 2nd 2012, 08:06 AM
mysur
Friction help
A book, which may be modelled as a particle of weight 8N rests in equilibrium on a desk top inclined at 28 degree to the horizontal. ind the frictional force acting on the book. he coefficients of friction between the book and the desk top is 0.6. Determine whether the equilibrium is limiting.

No clue

F = 8 sin (28)= 3.75
R= MF
= 0.3* 3.75

• Nov 2nd 2012, 11:54 AM
earboth
Re: Friction help
Quote:

Originally Posted by mysur
A book, which may be modelled as a particle of weight 8N rests in equilibrium on a desk top inclined at 28 degree to the horizontal. ind the frictional force acting on the book. he coefficients of friction between the book and the desk top is 0.6. Determine whether the equilibrium is limiting.

No clue

F = 8 sin (28)= 3.75
R= MF
= 0.3* 3.75

$|\overrightarrow{F_n}|=8 N \cdot \cos(28^\circ) \cdot 0.6\approx 4.24 N$
$|\overrightarrow{F_h}|=8 \cdot \sin(28^\circ) \approx 3.756 N$