Question

ratio of radius of gyration of a circular disc and circular ring of same mass and radius about a tangent axis parallel to their plane

Answer 1

Hello mate here is your answer.

Air Resistance Formula,

F = c x v^2.

For 20 Kmph, Given: F = R & v = 20 Kmph.

R = c x 400.
c = R/400.

For 40 kmph,

F = c x v^2.
F = (R/400) x 1600.
F = 4R.

Hope it helps you.