[填空题]
John drops a stone from the ted qcy8-ib;:g6cabt.mpmbp( rq+ 48xop of a cliff which is h 2l 3/ l9 koc: vvkb l86eh2ybyrjq8l1u)yi3djmetres above sea level. The stone strikes the water surface after32 /i)bbu1 l vdkyq:6jvjhe88r 2llloc3y yk9 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
1. Find the velocity of the stone when t=12 , giving your answer to the nearest $ \mathrm{m} \mathrm{s}^{-1} $.≈
2. Calculate the value of h , giving your answer to the nearest metre.≈
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.≈
