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 h = -16 t² + 52 t + 48, how long will it take for the rock to hit the water?

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.

a is the correct