Please answer it in a sentence from the picture below?

enter image source here

1 Answer
May 12, 2018

7 seconds in air and 5 seconds in water

Explanation:

First thing to do is to draw a diagram.

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Let the distance from the cliff to the sea be h "m", and the time taken to drop this be t"s". This would mean the distance from the sea to the seabed is (127-h)"m" and the time taken is "(12-t)"s"

We can use "speed"="distance"/"time" to make two equations to solve simultaneously.

For air:

16=h/t
h=16t" " (1)

For water:

3=(127-h)/(12-t)
3(12-t)=127-h
36-3t=127-h
-3t=91-h
3t=h-91" " (2)

Substituting (1) into (2) we get:

3t=16t-91
-13t=-91
13t=91
t=7

So the stone drops for 7 seconds in air.

Since the total time the stone drops for is 12"s", the time taken for it to fall in the water =12-7=5"s"