NEETPhysicsRotational Motion
If radius of the earth is reduced to half without changing its mass, then match the following columns ( array |c|l|c|l| & Column I & & Column II (A) & Angular momentum & (p) & Will become two times & of the earth & & (B) & Time period of rotation & (a) & Will become four times & of the earth & & (C) & Rotational kinetic energy & (r) & Will remain constant & of the earth & & & & (s) & None of the above array )
Options
- Aa-r b-s c-p
- Ba-s b-r c-p
- Ca-r b-s c-q
- Da-q b-p c-s
Correct answer
C. a-r b-s c-q
Step-by-step solution
In the absence of external torque, angular momentum remains constant. ( gathered L=I = constant I R^2 gathered ) ( I ) will remain ( 1 4 ) th or ( ) will become 4 times. Therefore, time period ( (T )) will remain ( 1 4 ) th Further, (K= L^2 2 I ) Since, angular momentum is constant and I has become ( 1 - th ). Therefore, kinetic energy will become 4 times.