If the polar ice caps of the earth were to melt, what would the effect of the length of the day be?
Answer:
Earth rotates about its polar axis. When ice of polar caps of earth melts, mass concentrated near the axis of rotation spreads out. Therefore, moment of inertia I increase.
As no external torque acts, angular momentum constant.
i.e L = Iω = I(2π/T)
With increase of I, T will increase i.e. length of the day will increase.