A. 237 N. The force of kinetic friction acting on him as he slides across the floor is Fk ≅ 237 N.
The equation of the force of kinetic friction is given by Fk = μk*N, where n = m*g. We know that the coefficient of kinetic friction between Gary's shoes and the wet kitchen floor is μk = 0.21, and Gary has a mass of 115kg. Substituting the values:
Fk = μk*n
Fk = (0.21)(115kg*9.8m/s²)
Fk = 236.67 N
Fk≅ 237 N