A thin metal disc of radius `0.25m` and mass `2kg` starts from rest and rolls down an inclined plane. If its rotational kinetic energy is `4J` at the foot of the inclined plane, then its linear velocity at the same point is

Answer

A, B

Explanation

Here, `r=0.5, m=2kg`
Rotational KE `=(1)/(2)l omega^(2)=(1)/(2)xx((1)/(2)mr^(2))omega^(2)`
`"or "4=(1)/(4)mv^(2)=(1)/(4)xx2v^(2)`
`rArr" "v=sqrt8=2sqrt2ms^(-1)`