Question

What horizontal force P can be applied to a 100-kg block in a level surface with coefficient of friction of 0.2, that will cause and acceleration of 2.50 m/s2?

Answer 1

$$ma=F-F_f\\ ma=F-\mu mg$$

$$F=m(a+\mu g)\\ ={100\:\rm kg*(2.50\:\ m/s^2+0.2*9.8\:m /s^2)}\\ =446\:\rm N$$