Question

A raindrop of mass 1.5 g falling from a height of 9.8 km strikes the ground with a speed of 40 m/s. Find the loss of its PE and KE. If the drop experices a resistive force what is the work done against this force g=9.8 m/s

Answer 1

Potential energy at the heights point = 0
Potential energy on the ground= mgh
=1.5*9.8*1000*9.8=144060J

Change in potential energy= 0-144060=144060J


Kinetic energy at the highest point = 1/2*m*vsq
=1/2*1.5*40*40=1200J

Kinetic energy on the ground =0
Change in Kinetic energy = 1200-0=1200J


According to work energy theorem,
Change in Kinetic energy = work done
Work=1200J


Hope it helps you