Finding acceleration using static/kinetic friction, mass & applied force?

[emall16]

Homework Statement

a fridge with a mass of 120kg is at rest on a kitchen floor. If Ms is 0.32 and Mk is 0.28 and you apply 472N of force what will be the acceleration of the fridge?

m=120kg
Ms=0.32
Mk=0.28
Fa=472N

Homework Equations

Ff=MFn

Fw=mg
Fw=1176N
Fn=1176N

F=ma

The Attempt at a Solution

not sure how to start solving for acceleration. was thinking that i needed to find the net force so that i could plug it into F=ma and solve for acceleration, but i am unsure how to find net force from the given information. could use the Ff=MFn equation but I am not sure whether to plug in static or kinetic friction. any help is appreciated, thank you!

 

[CWatters]

There are two steps to the problem...

Is the applied force enough to overcome the static friction? If not the fridge won't move so acceleration = 0.

If it is then your approach is correct. Use Mk in the equation.

Basically as soon as it starts moving friction drops from Ms to Mk. So you can ignore Ms when working out the net force.