What is the net force on the box when a 15 N horizontal force is applied to the box?

Question

The coefficient of the static and kinetic frictions between a 3.0-kg box and a desk are 0.40 and 0.30, acceleration of -2.45 m/s^2. What is the net force on the box when a 15 N horizontal force is applied to the box?

Answer 1

F - µmg = 15 - .3*3*9.8 = 6.18 N