The speed of a tsunami s (in meters/second) is approximated by s=√gd , where g is the acceleration due to gravity (9.8 m/s2) and d is the depth of the water (in meters). If the speed of a tsunami is 200 m/s, about how deep is the water?

Use the formula, fill in the known variables, and solve for d.

s = sqrt(gd)

200 m/s = sqrt(9.8 m/s^2 * d)

Square both sides.

40000 m^2/s^2 = 9.8d m/s^2

9.8d = 40000 m

d = 40000/9.8 m

d = 4082 m