Starting from rest, the cable can be wound onto the drum of the motor at a rate of vA = (3t 2) m>s, where t is in seconds. Determine the time needed to lift the load 7 m.

Problem 12-201Starting from rest, the cable can be wound onto the drum of the motor at a rate of v = (3t ) m/s, Awhere t is in seconds. Determine the time needed to lift the load 7 m. Step-by-step solution Step 1 of 4Write the relation for the length of the string 1. sB+ (s Bs )C= l 1 2sB s C l 1Here, s B s C are the lengths of the strings from the fixed supports to the corresponding points.Differentiate the equation once with respect to time. 2v v = 0 ……….(1) B C v C 2v BHere, v B v C are the velocities corresponding to points B and C respectively.