A star is rotating with a period of 10.0 days. It collapses with no loss in mass to a white dwarf with a radius of .001 of its original radius.
a) What is its initial angular velocity?
b) What is its angular velocity after collapse?

Part a)

Initial angular speed of the star is

Part b)

Final angular speed of the star after it collapse is given as

Explanation:

Part a)

As we know that angular speed is given as

now we have

Part b)

As we know that star collapses due to its own force

So here we can say that angular momentum is conserved here

So we have

current and voltage can both be different in different parts of a circuit so it matters where you place the ammeter and voltmete