A pebble drops from a balcony that is 80 feet above the ground. The pebble lands on the top of a sign that is 16 feet high. The function y=80−16t2 represents the height y (in feet) of the pebble t seconds after dropping from the balcony. How many seconds does the pebble drop before hitting the sign?
The pebble hits the sign after
seconds.
