Question

Can Anyone Solve Question Number 28, Please

Answer 1

let t is the time of free fall of body
at last second means (t-1) sec velocity of body
v'=0-g (t-1)
v'=-g (t-1) -----(1)
when body strike surface of earth then velocity of body
v=0-gt
v=-gt --------(2)
now displacement in last second
v^2=v'^2+2as
g^2t^2=g^2 (t-1)^2-2gs
-s=(g^2t^2-g^2t^2+2g^2t-g)/2g
=(2gt-g)/2

s=1/2 (1-2t) g
now displacement in first 3second =ut+1/2at^2=0-1/2g (3)^2=-45 m
a/c question
1/2g (1-2t)=-45
1/2g (2t-1)=45
t=5 sec

Answer 2

Answer:

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