If earth shrinks to 1/64 of its volume with mass remaining same, duration of the day will be
1.5h
3h
4.5h
6h
Iω=25MR2ω= constant and V∝R3
as v decreases by 64 times R decreases by 4 times and moment of inertia decreases by 16 times and ω increases by 16 times T decreases to 16 times.