Question

A stone is dropped from a roof it takes 2sec to reach the ground what is the height of the building

Answer 1

hey
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as its dropped so intial velocity (u)=0
g = 9.8 m/s
time (t )= 2s
height = ?

we know from second equation of motion

s= ut +1/2gt^2
h = 0*t + 1/2*9.8*2*2
h= 9.8*2
h = 19.6 m

hence height is 19.6 m

hope Helped
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Answer 2

For freely falling body, i.e . dropped from a roof or etc...
Height of the building= 1/2 × acceleration due to gravity×(time)²
=> H = ½gt²
Now H = (½×9.8×2²)m =(9.8 ×2)m
= 19.6 m
If g= 10 m/s then
H = (½× 10×2²)m
=(10×2) m
= 20m
HOPE IT HELPS...
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