Question

the height, h, in meters, of a gold ball t seconds after is is hit can be modelled by the function:

h (t) = 4.9t^2 + 32t + 0.2.

When is the height of the ball 15 m?

Answer 1

You have a typo, there should be a negative sign in front of 4.9t^2

so you want h(t) to be 5, ...

15 = -4.9t^2 + 32t + .2

4.9t^2 - 32t + 14.8 = 0

solve using the quadratic formula, you should get two positve answers, one will be the time on its upwards path, the other will be the time on its downwards path.
(should be appr. t=0.5 and t=6)

Answer 2

thanks so much Reiny! :D for correcting my mistake and for the answer!