Question

A pebble is tossed from the top of a cliff. The pebble's height in feet is given by y(t) = -16t2 + 6t + 200, where t is the time in seconds. Its horizontal distance in feet from the base of the cliff is given by d(t) = 5t.
How far will the pebble be from the base of the cliff when it hits the ground? Round to the nearest foot. _______ ft Use a number only.

Answer 1

y(t) = 0 

16t^2 - 6t - 200 = 0

2 (8t^2 - 3t  -100) = 0

t = (3 +/- √3209)/16

d(t) = 5 x (3 +/- √3209)/16

= 19 from the base of the cliff

hope this helps