Answer:
a = 0.5 [m/s²]
Explanation:
To solve this problem we must use Newton's second law which tells us that the sum of forces is equal to the product of mass by acceleration.
ΣF = m*a
F = force = 200 [N]
m = mass = 400 [kg]
a = acceleration [m/s²]
Now replacing:
200 = 400*a
