Answer to Question #97347 in Mechanics | Relativity for Christopher lucky

Question

a block a mass 50kg slides down a plane inclined at an angle 30 to the horizontal. if the coefficient of friction is 0.4 calculate the frictional force btwn the two surfaces (g=10m/s)

Answer 1

The friction force by definition

$F=\mu N$

The normal reaction force is given by

$N=mg\cos\theta$

So

$F=\mu mg\cos\theta$

$=0.4\times 50\:\rm kg\times 10\: m/s^2\times \cos 30^{\circ}=173.2\:\rm N$