Question

4. Density remaining constant, if earth contracts
to half of its present radius, duration of the
day would be (in minutes)
1) 45
2) 80
3) 100 4) 120​

Answer 1

Answer:

Now if density remains same, new moment of inertia will be I ′ = I/4

ω = Omega

And according to law of conservation of angular momentum (Iω)=(I ′ω')

ω ′ =4ω

Also, ω= 2π/T

and ω' =2π/T'

T ′ = T/4

T=24hrs

T ′ = 24/4

T ′ =6hrs=360minutes

Hence a day would be one-fourth of current duration.

Note - But the options are note relevant to the answer

Answer 2

Answer:

ans is 45 mins hope it helps you