Question

A feather of mass 0.001 kg falls from a height of 2 m. Under realistic conditions, it experiences air resistance. Based on what you know about friction, what can you say about the kinetic energy of the feather as it reaches the ground? Acceleration due to gravity is g = 9.8 m/s2.
A. KE < 0.0196 J
B. KE = 00196 J
C. JE = 0 J
D. KE > 0.0196 J

Answer 1

As per initial given conditions first we will find the initial potential energy of the feather

$U = mgh$

$m = 0.001 kg$

$g = 9.8 m/s^2$

$h = 2m$

$U = (0.001kg)(9.8 m/s^2)(2m)$

$U = 0.0196 J$

now we know that few amount of its initial energy is lost in form of frictional energy loss

so remaining energy will be less than the initial potential energy

So final answer would be

A. KE < 0.0196 J