Answer:
The answer is 0.83 seconds.
Explanation:
The formula of free fall is following:
[tex]h=1/2*g*t^2[/tex]
Where g=9.8 m/s^2 and t=2 seconds, the rock takes:
[tex]h=1/2*9.8*2^2=19.6[/tex]
19.6 meters. This is the half distance of the cliff. The whole distance is 39.2 meters. So it takes:
[tex]39.2=1/2*9.8*t^2\\t^2=8\\t=2.83[/tex]
2.83 second to fall down completely. The rock takes the second half of the cliff in 0.83 seconds
