Consider a drop of rain water having mass 1g falling from a height of 1km. It hits the ground with a speed of 50m/s. Take 'g' constant with a value 10m/s². The work done by the (i) gravitational force the (ii) resistive force of air is:

The correct option is A
(i)10J(ii)−8.75J
m=1g=1/1000kg
h=1km=1000m
work done by gravitational force wg = mgh
wg=1/1000 × 10 × 1000
wg = 10J
Change in kinetic energy ΔK.E=1/2mv²
ΔK.E=1/2(1/1000) × 50 × 50
ΔK.E=1.25J
Work energy theorem: wg + wair resistance = ΔK.E
10J + wair resistance = 1.25
wair resistance = −8.75J