In diving to a depth of 308 m, an elephant seal also moves 579 m due east of his starting point. what is the magnitude of the seal's displacement?

655.82m

Explanation:

By tracing the distances traveled from 308m down in the water and then 579m to the east, a right triangle can be formed and the displacement can be found by the Pythagorean theorem. This is shown in the attached image (the red line is the displacement).

One leg of the triangle will be the 308m

and the second leg of the triangle will be the 579m.

If we call the displacement , by the pythagorean theorem:

The displacement is 655.82m

at positions a, g kinetic energy is maximum.

at position d, potential energy is maximum.