A waterfall has a height of 1900 feet. A pebble is thrown upward from the top of the falls with an initial velocity of 12 feet per second. The height, h, of the pebble after t seconds is given by the equation h=-16t^2+12t+1900. How long after the pebble is thrown will it hit the ground?

Step-by-step explanation:

h is the height of the pebble after a certain amount of time has gone by. Since we are told to find that time when the pebble is on the ground, we say that h = 0 since the height of something on the ground has no height at all. Then factor the quadratic.

Throw that into the quadratic formula or however you were taught to factor irrational quadratics (maybe completing the square?) to get that

t = 11.27869 sec and t = -10.52869 sec

Since we all know that time will never carry a negative value, we will disregard it and go with 11.27869 seconds. Not sure to where you are told to round.

28

step-by-step explanation:

8+8+6+6