A ball is thrown from a height of 123 feet with an initial downward velocity of 11/fts. The ball's height h (in feet) after t seconds is given by the following.
h=123−11t-16t^2
How long after the ball is thrown does it hit the ground?

Question

A ball is thrown from a height of 123 feet with an initial downward velocity of 11/fts. The ball's height h (in feet) after t seconds is given by the following.
h=123−11t-16t^2
How long after the ball is thrown does it hit the ground?

anonymous · Answer

@whpalmer4 Can you help me with this one?

whpalmer4 · Answer

okay, here you need to find the values of $t$ where $h=0$

whpalmer4 · Answer

one of them will be negative, and can be disregarded

anonymous · Answer

So how would I do that?

whpalmer4 · Answer

Same way you did the other one?

whpalmer4 · Answer

$$0 = 123-11t-16t^2$$

anonymous · Answer

Would I be solving for h?

anonymous · Answer

I got t= -11/32 + 1/32sqrt7993 and t=-11/32 + -1/32sqrt7993

whpalmer4 · Answer

no, you know h = 0, you're solving for values of t that make that true. and it looks like you got them correct :-)

anonymous · Answer

And the numerical values would be -3.34 and 2.45 ?

anonymous · Answer

-3.14**

whpalmer4 · Answer

yes, that's right