How fast can a hoist lift a 326 kg load with 12.6 kw of power?

[DethRose]

I have a work and power problem but I am not sure what it has to do with the work and power formulas and have no idea how to solve it.

The question is

with what speed can a lifting hoist rated at 12.6 kw raise a 326 kg load?

i found distance to be 9401.94 but that's as far as i got

help please

thanks

 

[HallsofIvy]

You found the "distance to be 9401.94"? What distance??

12.6 kw is 12600 Joules per hour. In One Hour, it does 12600 Joules of work which corresponds to ( since w= mgh, (326)(9.81)h= 12600 ) 3.94 meters. It can only lift the 326 kg load at 3.94 meters per hour!

 

[JinSu]

Did you try using

P = Fv
W = Fx

Because those two formula would give you the answer for velocity/speed by rearranging the variables around.

 

[dextercioby]

You found the "distance to be 9401.94"? What distance??

12.6 kw is 12600 Joules per hour. In One Hour, it does 12600 Joules of work which corresponds to ( since w= mgh, (326)(9.81)h= 12600 ) 3.94 meters. It can only lift the 326 kg load at 3.94 meters per hour!

What hour...? U mean second... GDit.It gives the power:the power is force times speed.
The power is 12.6 KW=12600W.The force is nothing but the gravity:
F=mg=326kg*9.80665ms^(-2)=3196,9353N approx=3197N
Speed is power over force:
v approx=12600W/3197N approx=3.94 m/s.That is METERS PER SECOND...

Daniel.

EDIT:The natural multiples of ten are usually noted by capital letters.
$$10^{3}\rightarrow K$$ apud "Kilo".Kg,Km,KW,KJ,KN,...