The formula for the force of Kinetic friction is:
[tex]F_{k} = [/tex]μ*N
Please consider μ as the coefficient of the kinetic friction = 0.2
N = Normal to the desk = m*g = 3.5 * 9.8 = 34.3 N
[tex]F_{k} = [/tex] Force of Kinetic Friction = ?
Therefore,
The force of Kinetic Friction = [tex]F_{k} = [/tex] 0.2 * 34.3
[tex]F_{k} = [/tex]6.86N
The size of force of Kinetic Friction = 6.86N.
