A feather of mass 15 g is dropped from a height. It is found to fall with a constant velocity. What is the net force acting on it ?

The correct option is Zero.

Step-by-step Explanation:

1. Identify the given information:
Mass of the feather, m = 15 g
The feather falls with a constant velocity.

2. Apply Newton's First Law / Second Law of Motion:
Newton's Second Law states that the net force $F$ acting on an object is equal to the mass of the object multiplied by its acceleration $a$:

$F=m·a$

Since the feather is moving with a constant velocity, its rate of change of velocity (acceleration $a$) is zero:

$a=0{\text{ m/s}}^2$

3. Calculate the net force:

$F_{\text{net}}=m·0=0\text{ N}$

Therefore, the upward resistive air drag forces balance out the downward gravitational force acting on the feather, resulting in a net force of Zero.