
If polar ice caps melts, then the angular rotation of the earth :
A) increases
B) decreases
C) remains constant.
d) depends on when the ice melts.
Answer
125.7k+ views
Hint: Use the Concept of Moment of inertia(I) as we move away or towards the centre (in this case equator to pole or pole to equator) .
Step by Step Solution
Earth can be considered as a sphere.Now, if ice in the polar region melts,the resulting water will flow towards the equator and consequently moment of inertia(I) of the earth will increase as more mass has accumulated at the equator which is more distant from the rotational axis as compared to the poles.So, from the law of Conservation of Angular Momentum (COAM) we have -
$Iw$= constant (where I= moment of inertia and w= angular velocity)
We can see that if I will increase w has to decrease to keep the value constant.
In this case , as I increases w has to decrease and hence angular velocity decreases when ice melts at polar region.
Note
1) If the moment of inertia increases, then angular velocity decreases (Iw= constant).
2) Time period increases ($T = \dfrac{{2\pi }}{w}$). Since the time period increases, the duration of the day becomes longer.
3) The condition of zero net angular impulse is required for conservation of angular momentum.
4) Other examples of conservation of angular momentum are -
a)Spinning ice skater.
b)Student on rotating turntable.
Step by Step Solution
Earth can be considered as a sphere.Now, if ice in the polar region melts,the resulting water will flow towards the equator and consequently moment of inertia(I) of the earth will increase as more mass has accumulated at the equator which is more distant from the rotational axis as compared to the poles.So, from the law of Conservation of Angular Momentum (COAM) we have -
$Iw$= constant (where I= moment of inertia and w= angular velocity)
We can see that if I will increase w has to decrease to keep the value constant.
In this case , as I increases w has to decrease and hence angular velocity decreases when ice melts at polar region.
Note
1) If the moment of inertia increases, then angular velocity decreases (Iw= constant).
2) Time period increases ($T = \dfrac{{2\pi }}{w}$). Since the time period increases, the duration of the day becomes longer.
3) The condition of zero net angular impulse is required for conservation of angular momentum.
4) Other examples of conservation of angular momentum are -
a)Spinning ice skater.
b)Student on rotating turntable.
Recently Updated Pages
JEE Main 2023 (April 8th Shift 2) Physics Question Paper with Answer Key

JEE Main 2023 (January 30th Shift 2) Maths Question Paper with Answer Key

JEE Main 2022 (July 25th Shift 2) Physics Question Paper with Answer Key

Classification of Elements and Periodicity in Properties Chapter For JEE Main Chemistry

JEE Main 2023 (January 25th Shift 1) Maths Question Paper with Answer Key

JEE Main 2023 (January 24th Shift 2) Chemistry Question Paper with Answer Key

Trending doubts
JEE Main 2025 Session 2: Application Form (Out), Exam Dates (Released), Eligibility & More

JEE Main Login 2045: Step-by-Step Instructions and Details

Class 11 JEE Main Physics Mock Test 2025

JEE Main Exam Marking Scheme: Detailed Breakdown of Marks and Negative Marking

JEE Main 2023 January 24 Shift 2 Question Paper with Answer Keys & Solutions

JEE Mains 2025 Correction Window Date (Out) – Check Procedure and Fees Here!

Other Pages
JEE Advanced Marks vs Ranks 2025: Understanding Category-wise Qualifying Marks and Previous Year Cut-offs

JEE Advanced 2025: Dates, Registration, Syllabus, Eligibility Criteria and More

NCERT Solutions for Class 11 Physics Chapter 1 Units and Measurements

NCERT Solutions for Class 11 Physics Chapter 9 Mechanical Properties of Fluids

Units and Measurements Class 11 Notes: CBSE Physics Chapter 1

NCERT Solutions for Class 11 Physics Chapter 2 Motion In A Straight Line
