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## Homework Statement

A ball is dropped from the top of a cliff. If time taken for half of the descent is 3s, then what is the time taken for the rest of rest of the descent? Take g=10m/s

^{2}

## Homework Equations

T=√(2h/g)

v=u-gt

s=ut-gt

^{2}/2

## The Attempt at a Solution

T=√(2h/g)

h=T

^{2}g/2=45m

∴height of cliff=90m

v=u-gt=0-(10*3)=-30ms

^{-1}

s=ut-gt

^{2}/2

45=-30t-5t

^{2}

t=-3

Looks wrong to me. Time can't be negative, can it? Also, shouldn't the answer be less than 3?