The final answer is "39 ft/s".
Determine the string's length.
[tex]S_A +2S_B +2S_C = Constant[/tex]
Calculate the equation in terms of time.
[tex]v_A+2v_B +2v_c =0 \\\\6 +2v_B +2(18)=0 \\\\2v_B = -42 \\\\V_B =-21 \frac{ft}{s}[/tex]
Calculate the relative velocity of B with respect to C.[tex]V_B = v_c + V_{\frac{B}{C}} \\\\-21=18+ V_{\frac{B}{C}} \\\\ V_{\frac{B}{C}}= -39 \ \frac{ft}{s} = 39 \ \frac{ft}{s} \uparrow[/tex]
Find out more information about the velocity here:
brainly.com/question/15088467
