A ball is dropped from top of a building.if the distance travelled by ball in the last third of total time is 10m,the height of building is

Answer 1

let t be the time of fall.

then
10=1/2 g (1/3t)^2+vi*2/3 t

but vi at the end of two thirds is
vi=g (2/3 t) so..

10=1/2 g (t/3)^2 + g (2/3t)^2
solve for time of fall, t
then, h=1/2 g t^2