Originally Posted by

**hazecraze** **A stone is dropped from the top of a 450 m tower. (Acceleration due to gravity is -9.8 m/s2. Ignore air resistance. Give your answers correct to two decimal places.)**

(a) Find the distance of the stone above ground level at time *t*.

$\displaystyle s(t)=$$\displaystyle 450 - \frac{9.81t^2}{2}$

(b) How long does it take the stone to reach the ground?

$\displaystyle 0 = 450 - \frac{9.81t^2}{2}$

$\displaystyle t = \sqrt\frac{(2 * 450)}{ 9.81} $

=$\displaystyle 9.58 sec.$

(c) **With what speed does it strike the ground?** This is the part I keep getting wrong.

$\displaystyle

v(t)=-9.8t$

=$\displaystyle -9.8(9.58)$

=$\displaystyle -93.97$