Question

A ball of mass 2 kg is dropped from a height what is the work done by its weight in 2 seconds after the ball is dropped​

Answer 1

HERE, mass,m=2 kg
distance it falls: 
h = ½gt² = ½(9.8)(2)² = 19.6 meters 
speed after 2 sec 
v = gt = 19.6 m/s 

PE lost = mgh = 2•9.8•19.6 = 384 J 
KE gained = ½mV² = ½(2)(19.6)² = 384 J 
now workdone =change in kinetic energy
at t=0 k.e=0
at t=2 k.e=384 joules
answer is 384 joules  {Ans.}