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A disc of radius 2 m and mass 100kg roll...

A disc of radius 2 m and mass 100kg rolls on a horizontal floor, its centre of mass has speed of `20 cm//s`. How much work is needed to stop it ?

A

1J

B

3J

C

30 KJ

D

2J

Text Solution

Verified by Experts

The correct Answer is:
B
work done `=DeltaKE`
`(KE)_(i)=(1)/(2)1omega^(2)+(1)/(2)1omega^(2)+(1)/(2)mv^(2)=(3)/(4)mv^(2)`
`=(3)/(4)xx100xx(20xx10^(-2))^(2)=(3)/(4)xx100xx400xx10^(-4)=3J`
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