The relation between force and mass and acceleration is
[tex]Force = mass X acceleration[/tex]
The SI unit will be
Force = Newton
mass =kg
acceleration=[tex]\frac{m}{s^{2} }[/tex]
thus
[tex]acceleration = \frac{Force}{mass}[/tex]
putting values
[tex]acceleration=\frac{60 N}{12kg}=5\frac{m}{s^{2} }[/tex]
Thus the acceleration will be
[tex]5\frac{m}{s^{2} }[/tex]