Squids are the fastest marine invertebrates, using a powerful set of muscles to take in and then eject water in a form of jet propulsion that can propel them to speeds of over 11.5 m/s. What speed (in m/s) would a stationary 1.60 kg squid achieve by ejecting 0.115 kg of water (not included in the squid's mass) at 3.50 m/s? Neglect other forces, including the drag force on the squid. HINT m/s

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skyluke89 skyluke89 · Answer 1 · 2019-06-18T04:19:36+02:00

Answer:

0.25 m/s

Explanation:

This problem can be solved by using the law of conservation of momentum - the total momentum of the squid-water system must be conserved.

Initially, the squid and the water are at rest, so the total momentum is zero:

[tex]p_i = 0[/tex]

After the squid ejects the water, the total momentum is

[tex]p_f = m_s v_s + m_w v_w[/tex]

where

[tex]m_s = 1.60 kg[/tex] is the mass of the squid

[tex]v_s[/tex] is the velocity of the squid

[tex]m_2 = 0.115 kg[/tex] is the mass of the water

[tex]v_w = 3.50 m/s[/tex] is the velocity of the water

Due to the conservation of momentum,

[tex]p_i = p_f[/tex]

so

[tex]0=m_s v_s + m_w v_w[/tex]

so we can find the final velocity of the squid:

[tex]v_s = -\frac{m_w v_w}{m_s}=-\frac{(0.115 kg)(3.50 m/s)}{1.60 kg}=-0.25 m/s[/tex]

and the negative sign means the direction is opposite to that of the water.