Question

Statement 1: If polar ice melts, days will be longer.

Statement 2: Moment of inertia decreases and thus angular velocity increases.

(a) Both statement 1 and 2 are true and statement2 is the correct explanation of the statement1

(b) Both statement 1 and 2 are true but the statement2 is not the correct explanation of the statement1

(c) Statement 1 is true but statement 2 is false

(d) Statement 1 and 2 are false

I had been asked this question in an international level competition.

This is a very interesting question from Moment of Inertia and its Significance topic in portion System of Particles and Rotational Motion of Engineering Physics I

Answer 1

Right choice is (a) Both statement 1 and 2 are true and statement2 is the correct explanation of the statement1

To explain: As the polar ice melts, water so formed flows towards the equator. The moment of inertia of the earth increases. To conserve angular momentum, angular velocity decreases. This increases the length of the day.