Newton's Second Law:

* F = m * a

where:

* F = Force (measured in Newtons, N)

* m = Mass (measured in kilograms, kg)

* a = Acceleration (measured in meters per second squared, m/s²)

Given:

* m = 0.040 kg

* a = 400 m/s²

Solving for Force (F):

* F = (0.040 kg) * (400 m/s²)

* F = 16 N

Therefore, a force of 16 Newtons would be needed to accelerate the golf ball at 400 m/s².