Question

What is the acceleration of this object? The object's mass is 60 kg.

Answer 1

The answer is 3.3 m/s^2 (m/s squared)

Answer 2

We know, F = m*a
Here, F = 600-400 = 200 N downwards 
m = 60 Kg

Substitute their values, 
a = 200/60
a = 20/6
a = 10/3
a = 3.33 m/s² downwards

In short, Your Answer would be 3.33 m/s² downwards

Hope this helps!