Answer:
a) F = 353.2 N
b)

a = 4.21 m/s²
Step-by-step 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!