A box of mass 60 kg is at rest on a horizontal floor that has a static coefficient of friction of 0.6 and a kinetic coefficient of 0.25 a)The minimum force necessary to start moving the box
b) The friction force and the acceleration of the box if a horizontal force of 400 N is applied

a) F = 353.2 N

b)

   a = 4.21 m/s²

Explanation:

a) The minimum force necessary to start moving the box s given by:       

Where:

F: is the force applied to move the box

μs: is the static coefficient of friction = 0.6          

m: is the mass = 60 kg

g: is the gravity = 9.81 m/s²

b) The acceleration is:

Now, the friction force is:

I hope it helps you!    

this could be newton#'s law of cooling. the cooling curve is exponential