Mollusks

Cephalopod Propulsion

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All cephalopods live in oceans and are adapted for swimming. The squid and other cephalopods have a water-filled cavity between and outer muscular covering and it's internal organs. When the animal tightens its muscular covering, water is forced out through an opening near the head. According to Newton's third law of motion, when one object exerts a force on a second object, the second object exerts a force on the first that is equal and opposite in direction. the movement of these animals are an example of this law. Muscles exert force on water under the mantle. This movement allows the muscle to move backwards.

A squid can propel itself at the speed of more than 6m/s using its jet propulsion. The squid is so fast that it can briefly  outdistance whales, dolphins, and the fastest fish. Also the squid can even jump out of the water and reach heights of almost 5 meters above the surface of the water. It can travel through the air as far as 15 meters. However, they can only keep this up for just a few seconds. Octopuses also use jet propulsion.