Question

A stone falls from the top of a cliff into the ocean. In the air, it had an average speed of 1616 \text{m/s}m/s. In the water, it had an average speed of 33 \text{m/s}m/s before hitting the seabed. The total distance from the top of the cliff to the seabed is 127127 meters, and the stone's entire fall took 1212 seconds. How long did the stone fall in air and how long did it fall in the water?

Answer 1

Answer:

time in air is 7 seconds

Time in water is 5 seconds

Step-by-step explanation:

Let's assume

time took in air =t seconds

we are given

the stone's entire fall took 12 seconds

so, time took in water =12-t

now, we can find distance traveled in air

In the air, it had an average speed of 16m/s

time took in air =t seconds

we know that

distance = speed *time

distance  in air= 16*t

In the water, it had an average speed of 3m/s

time took in water =12-t

we know that

distance = speed *time

distance in water= 3(12-t)

now, we can find total distance

total distance = distance in air + distance in water

so, total distance =16t+3(12-t)

we are given

total distance =127

we can set them equal

$127=16t+3(12-t)$

now, we can solve for t

$13t+36=127$

$13t=91$

$t=7$

now, we can find time took in water

time took in water=12-7=5