Problem
The circular disc of radius 𝟓𝒎 is divided into 7 equal parts and colored in the sequence "𝑽𝑰𝑩𝑮𝒀𝑶𝑹". What is the minimum velocity at which it will seem white to a human? (Persistence of human vision is 𝟎.𝟏𝒔
Solution
We know, velocity v = distance 𝒔/time t.
=> v = 2πr/t
=> v = 2×3.1416×5/0.1
=> v = 314.16 𝒎𝒔-1
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