# A stuntman jumps from the roof of a building to a safety net below. How far has the stuntman fallen after 1.6 seconds?

Dec 3, 2015

I found $12.5 m$
${y}_{f} - {y}_{i} = {v}_{i} t + \frac{1}{2} a {t}^{2}$
where $i \mathmr{and} f$ refer to the initial and final positions: The initial position can be chosen as zero height and with your data, with ${v}_{i} = 0$ and using $g = - 9.8 \frac{m}{s} ^ 2$ (because directed downwards) we get:
${y}_{f} - 0 = - \frac{1}{2} \left(9.8\right) \cdot {\left(1.6\right)}^{2}$
${y}_{f} = - 12.5 m$ below the starting point at ${y}_{i} = 0$ considered at the origin.