[填空题]
A person jumps off a diving board 4.0bfuvl 7:4 z*ek0hr lsx-3r3 duw2h-vw-rn5of m above the water’s surface into a demq4 9z q ehub,ou49l:rep pool. The person’s downward motion stops eoh9b 44 r:,umzuq9ql2.0 m below the surface of the water. Estimate the average deceleration of the person while under the water. $\approx$ $m/s^2$ (Round to the nearest integer)