## Matt71 3 years ago The height, "h" m, of a golf ball at time, "t" s, from the ground is given h=-5t^2+15t. a.) Find the time of flight of the golf ball. **solutions will be appreciated

1. apoorvk

find the two times when height "h" is zero. equate the equation to zero for that. now the smaller 't' will be the time when the ball was launched and the larger 't' value wil be the time when the ball landed. deduct the two to get the Time Period.

2. Recursing

The ball ends it's flight when it height reaches 0, right? so \[0=-5t^2+15t\]

3. amistre64

i would say there are to many assumptions to be had in order to make a proper determination

4. Recursing

why?

5. Matt71

braaaiiiiiin poop, all I know is it has something to do with a parabola

6. amistre64

|dw:1334427906699:dw|

7. amistre64

|dw:1334427942407:dw|

8. amistre64

mostly terrain issues :)

9. Matt71

That's actually just one of the questions. These are all of them: a)Find the time of flight of the golf ball b)Draw the graph of h=-5t^2+15t during the time of flight c)Find the maximum height of the golf ball from the ground d)when is the golf ball 8m above the ground?

10. Recursing

Yes, but you know the height from the ground, I suppose it's the ground directly beneath the ball.

11. amistre64

like a flyball

12. Matt71

So, is there anyway to get an exact answer with the information given?

13. amistre64

cant make it to the hole if you just hit it straight up

14. Recursing

It doesn't have to be straight up.

15. Recursing

You know only the height, you don's know where it is.

16. amistre64

a)Find the time of flight of the golf ball h(t) = 0 b)Draw the graph of h=-5t^2+15t during the time of flight draw an upside down parabola using the zeros found above and the vertex found in "c" c)Find the maximum height of the golf ball from the ground the vertex IS the high point d)when is the golf ball 8m above the ground? when h(t) = 8

17. apoorvk

well ofcourse a lot of assumptions are required, but when nothing's been stated, we take the simplest factors into account, i believe.