Answer:
If the object's charge is positive the field goes in the + x direction
If the object load is negative, the field must go in the -x direction
Explanation:
For this exercise let's use Newton's second law
F = m a
The force that acts is electric
F = q E
Let's replace
q E = m a
E = m a / q
We can see that the direction of the electric field depends on the ratio of the acceleration and the charge, in this case the acceleration is in the + x direction,
If the object's charge is positive the field goes in the + x direction
If the object load is negative, the field must go in the -x direction
