Question

If a freely falling body travels in the last second a distance equal to the distance travelled by it in the first three second the time of the travel is

Answer 1

for finding distance travelled in nth second,,use formula
s=u+a/2(2n-1)

let us assume that time of travel is n sec
so distance travelled in last sec i.e in nth sec is
s=0+g/2(2n-1)
s=5(2n-1)
which is equal to distance travelled in first 3 sec i.e
s=1/2g(3)^2
s=5(9)
s=45
so,
5(2n-1)=45
2n-1=9
n=8