A lift performs the first part of its ascent with uniform acceleration a and the remaining with uniform retardation 2a. If t is the time of ascent, find the depth of the shaft.

Retardation is double, Therefore, retardation time will be half.Let t0= acceleration timeThen, t02= retardation timet0+t02=t t0=2t3Now,s=s1+s2 =12(a)t02+12(2a)t022 =34at02=34(a)2t32 =at23