$$F_{net} = F_{gravity} + F_{air}$$

$$F_{net} = (1.4 \text{ kg})(9.8 \text{ m/s}^2) + (-2.5 \text{ N})$$

$$F_{net} = 13.72 \text{ N} - 2.5 \text{ N}$$

$$F_{net} = 11.22 \text{ N}$$

According to Newton's second law:

$$F_{net} = ma$$

Therefore, the acceleration of the object is:

$$a = \frac{F_{net}}{m}$$

$$a = \frac{ 11.22 \text{ N}}{1.4 \text{ kg}}$$

$$a = 8.014 \text{ m/s}^2$$

The acceleration of the object is 8.014 m/s^2 downward.