An object with a mass of 5 kg5kg is hanging from an axle with a radius of 12 cm12cm. If the wheel attached to the axle has a radius of 45 cm45cm, how much work would it take to turn the wheel a length equal to the circumference of the axle?

1 Answer
Nov 19, 2017

The work is =36.9J=36.9J

Explanation:

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The load is L=(5g)NL=(5g)N

The radius of the axle is r=0.12mr=0.12m

The radius of the wheel is R=0.45mR=0.45m

The effort is =(F)N=(F)N

The acceleration due to gravity is g=9.8ms^-2g=9.8ms2

Taking moments about the center of the axle

F*0.45=5g*0.12F0.45=5g0.12

F=5g*0.12/0.45=13.1NF=5g0.120.45=13.1N

The force is F=13.1NF=13.1N

The distance is d=2piR=2pixx0.45=(0.9pi)md=2πR=2π×0.45=(0.9π)m

The work is

W=Fxxd=13.1*0.9pi=36.9JW=F×d=13.10.9π=36.9J