Answer: It will take 4 seconds for the rock to hit the water.
Step-by-step explanation:
Given : Benjamin threw a rock straight up from a cliff that was 48 ft above the water.
If the height of the rock h, in feet, after t seconds is given by the equation
To find : Time taken for the rock to hit the water.
When rock hit the water height becomes zero , i.e. put h = 0 , we get
Divide equation by 2 , we get
The Laue of x for ax²+bx+c =0 is
So ,
Since t cannot be negative , so t= 4
Hence, it will take 4 seconds for the rock to hit the water.
