Answer
(a) The water should be expelled at a speed of 6.79 m/s.
(b) The squid creates 55.2 J of kinetic energy.
Work Step by Step
$p_s+p_w = 0$
$p_w = -p_s$
$m_wv_w = -m_sv_s$
$v_w = \frac{-m_sv_s}{m_w}$
$v_w = \frac{-(4.75~kg)(2.50~m/s)}{1.75~kg}$
$v_w = -6.79~m/s$
The water should be expelled at a speed of 6.79 m/s.
(b) $K = \frac{1}{2}m_sv_s^2+\frac{1}{2}m_wv_w^2$
$K = \frac{1}{2}(4.75~kg)(2.50~m/s)^2+\frac{1}{2}(1.75~kg)(6.79~m/s)^2$
$K = 55.2~J$
The squid creates 55.2 J of kinetic energy.
