Rotational MotionMedium
Question
If the earth were to suddenly contract to 
th of its present radius without any change in its mass then the duration of the new day will be nearly : -
th of its present radius without any change in its mass then the duration of the new day will be nearly : -Options
A.
hour
hourB.24n hour
C.
hour
hourD.24n2 hour
Solution
There is no exertial torque so the angular momentum remains constant as due to contraction the MI of earth decreases.
I2 =
Now I1ω1 = I2ω2 =
∴ T2 =
⇒ T2 = 
∴ T2 = 
I2 =
Now I1ω1 = I2ω2 =
∴ T2 =
⇒ T2 = ∴ T2 = Create a free account to view solution
View Solution FreeMore Rotational Motion Questions
In an experiment with a beam balance an unknown mass m is balanced by two known masses of 16kg and 4 kg as shown in figu...A thin circular ring of mass M and radius r is rotating about its axis with a constant angular velocity ω. The two ...A body is rolls on a rough curved surface with an initial speed v as shown in the figure if the body undergoing pure rol...A solid sphere $A$ of radius $R$ and mass $M$ is attached at a point to a smaller solid sphere $B$ of radius $r < R$ ...When a mass is rotating in a plane about a fixed point, its angular momentum is directed along:...