If the Earth were to suddenly contact to half its present radius, by how much would the day time decrease ?

If the Earth were to suddenly contact to half its present radius, by h

1.	If the Earth were to suddenly contact to half its present radius, by how much would the day time decrease ?
Answer» Solution :From the law of conservation of angular momentum, `I_1omega_J=I_2omega_2` where `omega_1=(2pi)/(T)` hence `(I_1)/(T_1)=(I_2)/(T_2)` where I=`2/5MR^2` if M remains the same, then `T_2=((R_1)/(R_1))^2.T_1((1R)/(2R))^2(24)=6`hr. `:. /_\T=24-6=18`hr. DECREASE in the period of ROTATION is 18 hr.