Question

Squids and octopuses propel themselves by expelling water. They do this by keeping water in a cavity and then suddenly contracting the cavity to force out the water through an opening. A 7.50 kg squid (including the water in the cavity) at rest suddenly sees a dangerous predator.

If the squid has 1.75 kg of water in its cavity, at what speed must it expel this water to instantaneously achieve a speed of 2.60 m/s to escape the predator? Neglect any drag effects of the surrounding water.

How much kinetic energy does the squid create by this maneuver?

Answer 1

Use momentum conservation principle to find the speed of the water and use the speed of water and squid to find the total kinetic energy created.