Answer
The person who dives into water is stopped over a longer distance and time period.
Work Step by Step
When a person jumps from a height of 10m into water, she is brought to rest over a distance of several meters, with a relatively small acceleration and a relatively small upward force from the water.
On the other hand, when a person jumps from a height of 10m onto concrete, though she lands at the same speed as before, she is brought to rest over a distance of millimeters, with a huge acceleration and an extremely large upward force from the ground.
