A generator having power and creating work for a crane

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Bassi
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Homework Statement


"A motor having an efficiencyof 88% operates a crane having an efficiency of 42%. With what constant speed doess the crane lift a 410-kg crate of machine parts if the power supplied to the motor is 5.5kW"
e'=42%
e=88%
m=410 kg
dr=?
de=?
t=?
g=9.8m/s square
fr=410x9.8=4018
p=5500 w
MA=?
IMA=?
wo=?
wi=?

Homework Equations


w=fd
p=w/t
ma=fr/dr
ima=de/dr
e=wo/wi then x100
e=ma/ima then x 100
wo=frdr
wi=fede
m=vd

The Attempt at a Solution


Im not sure if this is correct, but ill give it a shot:
p=w/d so p=frdr/t i think that since u r looking how fast the crane moves, you use 1 as t
so 5500=4018dr/1
so 5500/4018=dr
dr=1.36 so 1.36m/s
However the answer on the sheet says .50m/s so idont know? Please help as soon as possible.
-Bassi
 
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It might help you to know that mechanical Power = Force x Velocity at any instant. It should be clear what the minimum force required to lift the box is.