JEE Main 2020PhysicsGravitationEasyMCQ

JEE Main 2020 — Gravitation Question with Solution

JEE Main 2020 (05 Sep Shift 2)

Question

The acceleration due to gravity on the earth's surface at the poles is g and angular velocity of the earth about the axis passing through the pole is ω. An object is weighed at the equator and at a height h above the poles by using a spring balance. If the weights are found to be same, then h is: (h≪R, where R is the radius of the earth)

Choose an option

Show full solutionCorrect option: A
Correct answer
AR2ω22g

Step-by-step explanation

Acceleration due to gravity at height h above the pole

is given by

gh=g1-2hR  ...(1)

Acceleration due to gravity at the equator due to rotation of the earth is given by

g'=g−ω2R cos2λ  ...(2)

At the equator, λ=0

⇒g'=g−ω2R  ...(3)

As both weights are equal, i.e.; gh=g'

From equation (1) and (2), we get,
⇒ω2R=2gRh
∴h=R2ω22g

Practice this on the real CBT interface

Solve this JEE Main question (and the rest of the Gravitation chapter) on PrepSharp's TCS iON-style CBT player — with timer, bookmarks and session analytics.

Solve interactively →

About this question

This is a previous-year question from JEE Main 2020, covering the Gravitation chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.