Question

A ball is vertically projected upward from the ground. If the ball at height h at t=4s and 5s, what is the value of h?

Answer 1

100 m

If ball is at a given height at two different times t = t1 and t = t2 then from equation

h= ut -1/2gt2

1/2gt2-ut-h=0

(t1+t2) =2u/g   ..................eq 1

t1t2=2h/g       .................eq 2

from      eq  2 h =100 m