Newton's Second Law of Motion:

* Force (F) = Mass (m) x Acceleration (a)

Given:

* Mass (m) = 12 kg

* Acceleration (a) = 5 m/s²

Calculation:

* Force (F) = 12 kg * 5 m/s²

* Force (F) = 60 N (Newtons)

Therefore, a force of 60 Newtons is required to accelerate a 12 kg mass at 5 m/s².