# Question #ccb40

Mar 4, 2017

Explanation below:
- 10m
- 2sec

#### Explanation:

Start by setting $t = 0 \implies h = 10$, so the diver is 10m above the water line to start with.

When the diver hits the waterline, we can say that:

$h \left(t\right) = 0$

$\implies - 5 {t}^{2} + 5 t + 10 = 0$

$\implies {t}^{2} - t - 2 = 0$

Which we can factor as:

$\left(t - 2\right) \left(t + 1\right) = 0 \implies t = - 1 , 2$

The negative solution is nonsense, so the diver hits the waterline at $t = 2$s.