1. The problem statement, all variables and given/known data Your sofa won't fit through the door of your new sixth-floor apartment, so you use a 1.18 kW motor to lift the 84.7 kg sofa 18.8 m from the street. How much time does the lift take? 2. Relevant equations KE_i+PE_i=KE_f+PE_f (If forces are conserved? I'm not sure if so.) 3. The attempt at a solution KE_i=PE_f 1/2mv^2=mgh 1/2v^2=gh This leads to a dead end I think, velocity ends up being very large..