## 260. Math Puzzle $1 / 87$

Who has a greater speed: a 100-m runner who covers the distance in $10.3 \mathrm{~s}$, or a diver from a 10-m tower (free fall) when he enters the water?
Speed of the 100-m runner:

$$
v=\frac{s}{t}=\frac{100 \mathrm{~m}}{10.3 \mathrm{~s}}=9.709 \frac{\mathrm{m}}{\mathrm{s}}=34.952 \mathrm{~km} / \mathrm{h}
$$

Free fall of the diver:

$$
v=\sqrt{2 g \cdot s}=\sqrt{196.2 \mathrm{~m}^{2} \cdot \mathrm{s}^{2}} \approx 14 \frac{\mathrm{m}}{\mathrm{s}}=50.4 \mathrm{~km} / \mathrm{h}
$$

The diver from the 10 m tower has a significantly higher speed of $50.4 \mathrm{~km} / \mathrm{h}$ upon entry compared to the $100 \mathrm{~m}$ sprinter with almost $35 \mathrm{~km} / \mathrm{h}$.