The gently sloping submerged surface that extends from the shoreline toward the ocean basin floor is the continental

shelf.

Explanation:

The image attach, which you can find on internet with license to be reused, shows the shelf along with other surfaces from shore through the ocean.

The continental shelf is the landmass that is underwater next to the shore, it extends from the continent and comprisses an area of shallow water (the shelf sea)

Aslo, there is the shelf surrounding an island which is known as an insular shelf.

After the shelf you find a steep continental slope, followed by the flatter continental rise, and then the abyssal plain (the deepest surface).

Distance covered, s = 8ft - 4ft = 4 ftinitial velocity, u = 34 ft/sthe acrobat is moving upwards and therefore, a = -g = -9.81 m/s^2 = 32.19 ft/s^2applying equation of motion; s = ut -1/2gt^2then,4 = 34t -1/2*32.19t^24 = 34t - 16.095t^2rearranging; -16.095t^2 + 34t - 4 = 0solving the quadratic equation; t = {-34 +/- sqrt [34^2 - 4(-16.)]}/2(-16.095) = 1.06 +/- 0.93 = 0.13 or 1.99the acrobat will take 0.13 seconds to be at 8 ft above the ground. additionally, once at the maximum height, the acrobat will move down and be at the same spot (that is height) after 1.99 seconds moving down.

The fuzzy edges of shadows are a result of  diffraction