Answer : The forces were unequal, then they became equal.
Explanation : According to the attached complete question;
In the first part, where the velocity keeps on decreasing uniformly. The cart is observed to decelerate (here the acceleration is less than 0).
According to the formula of Force;
F = ma. (where F - Force; m - mass and a - acceleration)
when it was the case where a ≠ 0, there is a non-zero resultant force acting on the cart.
Therefore, the forces were unequal in the first part.
And during the second part, the velocity was observed to be constant, and so the acceleration is equal to 0.
Now, using the force formula;
F = ma.
As a = 0, the resultant force acting on the cart will also be 0.
Therefore, the forces are equal in the second part.