A 55-kg box rests on a horizontal surface. The coefficient of static friction between the box and the surface is 0.30. A 140-N force is applied to the box. What is the frictional force on the box?

161.7N

Explanation:

Given parameters:

Mass of the box  = 55kg

Coefficient of friction  = 0.3

Applied force  = 140N

Unknown:

Frictional force on the box = ?

Solution:

The frictional force on the box is a force that opposes the motion of the box.

To find the value of this force;

        Fr  = u m g

u is the coefficient of static friction

m is the mass

g is the acceleration due to gravity

 So;

     Fr  = 0.3 x 55 x 9.8  = 161.7N

snell's law

refractve index = sin incidence / sin refraction