Question

The net force acting on a leaf of mass $2g$ falling from a tree with a constant velocity is .

• A. 0 N
• B. 0.2 N
• C. 2 N
• D. 20 N

Answer 1

The correct option is A 0 N

We are given that the leaf is falling with a constant velocity.
$⟹a=0m{s}^{-1}$

From Newton's second law of motion,
$F=\frac{\Delta p}{\Delta t}=ma$
$F=0N$

Note that this is acheieved because the air resistance in the upward direction is equal to the force of gravity.