- #1
Capncanada
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Homework Statement
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?
Homework Equations
KE_i+PE_i=KE_f+PE_f
(If forces are conserved? I'm not sure if so.)
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..