Answer:
The running horizontal speed should be larger than 1.29 m/s.
Explanation:
In order for the swimmer to just miss the bone-breaking ledge, her horizontal speed must be
[tex]v > \frac{1.75m}{t_{fall}}[/tex]
in which we need to know how long we she be diving through the air. To determine that, recall the formula for the distance made by an object with acceleration (in this case it is the gravitational acceleration) with no initial (vertical) velocity:
[tex]s = \frac{1}{2}gt^2[/tex]
from which it follows that (for non-negative t)
[tex]t = \sqrt{\frac{2\cdot9m}{9.8\fram{m}{s^2}}}\approx1.36s[/tex]
This result can be used in the initial inequality:
[tex]v > \frac{1.75m}{t_{fall}}=\frac{1.75m}{1.36s}=1.29\frac{m}{s}[/tex]
The diving lady better gets a speed larger than 1.29 m/s to avoid landing on the ledge.
