Question

A body dropped from the top of a tower falls through hundred metres during the last two seconds of its fall . what is the duration of its fall ?
Pls guys don’t spam . And don’t send nonsense answers just for getting marks ‘cause a lots of ppl do that . Thanks !

Answer 1

let t be time taken
u=0
s in last 2s=s in total - s in (t-2)sec

100=ut+1/2at²-(u(t-2)+1/2a(t-2)²)

100=0+1/2at²-(0+1/2a(t²+4-2t))

100=1/2at²-(1/2at²+2a-at)

100=1/2at²-1/2at²-2a+at

100=-2a+at

100=-2*10+10*t

100+20=10t

t=120/10=12s