Question

A stone fell from the top of a cliff into the ocean. In the air, it had an average speed of 161616 \text{m/s}m/sstart text, m, slash, s, end text. In the water, it had an average speed of 333 \text{m/s}m/sstart text, m, slash, s, end text before hitting the seabed. The total distance from the top of the cliff to the seabed is 127127127 meters, and the stone's entire fall took 121212 seconds.

Answer 1

Answer:

Air-7sec

Water-5sec

Explanation:

-The average speed of the stone in air is given as $16m/s$, average speed in water is $3m/s$. And the total distance is $127m$.

Let speed in air be $v_1$ and in water $v_2,$ and $S$ is displacement:

$S=vt\\\\S=v_1t_1+v_2t_2\\\\127=16t_1+3t_2\\\\t_1+t_2=12s$

#Solving the simultaneous equations:

$t_1=12s-t_2\\\\127=16(12s-t_2)+3t_2\\\\127=192s-16t_2+3t_2\\\\t_2=5s\\\\t_1=12-5=7s$

Time in air is 7sec, Time in water is 5sec