Question

bio animal propulsion. 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 6.50 kg squid (including the water in the cavity) at rest suddenly sees a dangerous predator. (a) if the squid has 1.75 kg of water in its cavity, at what speed must it expel this water suddenly to achieve a speed of to escape the predator? ignore any drag effects of the surrounding water. (b) how much kinetic energy does the squid create by this maneuver?

Answer 1

To achieve a speed of zero when expelling water, the squid must expel the water at a speed of 0 m/s. The maneuver does not create any kinetic energy.

Step-by-step explanation:

To propel themselves, squid and octopuses expel water by contracting a cavity. In order to calculate the speed at which the squid must expel water to escape a predator, we can use the principle of conservation of momentum. Since the squid is at rest and no external force acts on it, the initial momentum is zero. When the squid expels water, it gains momentum in the opposite direction, causing it to move. The final momentum of the squid and water must be equal to the initial momentum of zero. To find the speed, we can use the equation mv = (m + water) × v'. Solving for v', we get v' = (m × v) ÷ (m + water), where m is the mass of the squid and v is the desired final speed. Substituting the given values, we have v' = (6.50 × 0) ÷ (6.50 + 1.75) = 0 m/s.

To calculate the kinetic energy created by the squid through this maneuver, we can use the equation KE = 0.5 × (m + water) × v'^2. Substituting the given values, we have KE = 0.5 × (6.50 + 1.75) × (0)^2 = 0 J.