Question

A pebble falls of a cliff at a height of 256 ft. If the equation for the height as a function is h(t)=-16^2 + initial height where t is time in seconds and h(t) is height in feet, how many seconds will it take for the pebble to hit the ground?

Answer 1

After 4secs

Explanation:

Given the function of the height expressed as;

h(t)=-16^2 + initial height

If initial height = 256, then;

h(t) = -16t^2 + 256t

The pebble will hot the ground at when h(t) = 0

Substitute

0 = -16t^2 + 256t

16t^2 = 256

t^2 = 256/16

t^2 = 16

t = 4

Hence the pebble will hit the ground after 4secs