1)A 2.0 kilogram wooden object is a on a wooden surface. What is the maximum force of friction that can be produced in this system?

 fr = 7.84 N

Explanation:

To solve this exercise we must use Newton's second law, the case of translational equilibrium

          F -fr = 0

          F = fr

where F is the applied force and fr the friction force

for the Y axis

          N -W =

          N = W

          N = m g

the friction force has the equation

           fr = μ N

            fr = μ m g

in this case they indicate the two materials that are in contact with wood on wood, so when reviewing the tables the coefficient of static friction is μ=0.4

let's calculate

             fr = 0.4 2.0 9.8

             fr = 7.84 N

see earlier