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A pulley 1 metre in diameter rotating at...

A pulley 1 metre in diameter rotating at 600 rpm is brought to rest in 80s by a constant force of frication on its shaft. How many revolutions does it make before coming to rest ?

A

200

B

300

C

400

D

500

Text Solution

Verified by Experts

The correct Answer is:
C
`omega_(1) = (600 xx 2pi)/(60) = 20 pi md//s, omega_(f)=0, t=80 s rArr omega =(0-2pi)/80 =-pi//4` rad `//s^(2)`
`rArr 0=(20pi)^(2) - 2(-pi //4)theta rArr 800 pi rArr` number of revolution `=theta/(2pi)=400`
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