The speed of the westbound cart before the collision is 4 m/s.
The given parameters:
The initial velocity of the second cart is determined by applying the principle of conservation of linear momentum.
[tex]m_1 u_1 + m_2 u_2 = v(m_1 + m_2)\\\\ 20(6) + 30(-u_2) = 0(20 + 30)\\\\ 120 - 30u_2 = 0\\\\ 30u_2 =120\\\\ u_2 =\frac{120}{30} \\\\ u_2 = 4 \ m/s[/tex]
Thus, the speed of the westbound cart before the collision is 4 m/s.
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