Question

im not good in math.

The Grand Canyon is 1600 meters deep at its deepest point; a rock is dropped from the rim above this point. Express the height of the rock as a function of the time t in seconds. How long will it tale the rock to hit the canyon floor?

can someone help me find the answer.

Answer 1

Height measured from the bottom?

height=1600-1/2 g time^2

how long to the bottom? When is h=0, do that, and solve for time

Answer 2

a) h(t) = -4.9t^2 + 1600

The rock hits the bottom of the canyon when the height is zero.
b) 0 = -4.9t^2 + 1600 ; 4.9t^2 = 1600 ; t^2 = 1600/4.9 = 326.53
t = square roots of 326.53 = 18.07 seconds