[填空题]
John drops a stone fromb 35ni ir54wf2k;u(zi k x0zao the top of a cliff which is h metresdqdxi8qp pxfn7 ) i*454zffr / above sea level. The stone strii)i5d*d/xqrp7z4x8 q ff4n f pkes the water surface after 9 seconds.
The velocity of the falling stone, $v \mathrm{~m} \mathrm{~s}^{-1}$, t seconds after John releases it, can be modelled by the function(round number)
1. Find the velocity of the stone when t=12 , giving your answer to the nearest $\mathrm{m} \mathrm{s}^{-1}$ .
v(12)≈ ms$^{-1}$.(round number)
2. Calculate the value of h , giving your answer to the nearest metre.
h≈ m,(round number).
The velocity of the stone when it reaches the bottom of sea is $10 \mathrm{~m} \mathrm{~s}^{-1}$ .
3. Determine the depth of sea near the cliff, giving your answer to the nearest metre.
d≈ m.
