Question

A waterfall has a height of 1300 feet. A pebble is thrown upward from the top of the falls with an initial velocity of 24 feet per second. The height of the pebble h in feet after t seconds is given by the equation h= - 16t^2 + 24t + 1300. How long after the pebble is thrown will it hit the ground? The time it takes for the pebble to hit the ground is about _ seconds.

Answer 1

Ok, so, this implies h=0 when the pebble hits the ground.

So, - 16t^2 + 24t + 1300 = 0

If we find t, we obtain two solutions, one negative and one positive, so the positive is correct.

Then, t = 9.7950 s

Therefore, it would take about 9.7950 seconds for the pebble to hit the ground.