## Physics (10th Edition)

Let up be the positive direction $x=ut+\frac{1}{2}at^{2}$ $u=\frac{x-\frac{1}{2}at^{2}}{t}$ $u=\frac{0-\frac{1}{2}(-9.8)(8.0)^{2}}{(8.0)}=39.2\; m/s$ Hence, the initial velocity is 39.2 m/s up.