JEE Main 2017PhysicsRotational MotionEasyMCQ

JEE Main 2017 — Rotational Motion Question with Solution

JEE Main 2017 (08 Apr Online)

Question

In a physical balance working on the principle of moments, when 5 mg weight is placed on the left pan, the beam becomes horizontal. Both the empty pans of the balance are of equal mass. Which of the following statements is correct?

Choose an option

Show full solutionCorrect option: B
Correct answer
BLeft arm is shorter than the right arm

Step-by-step explanation

Let m 1 and m 2 be the masses of pan

It is given that m1=m2



Since balance is achieved, so net torque about O should be zero.
5 mg+ m 1 g r 1 = m 2 g r 2
⇒5mg+m1gr1=m1gr2
⇒r1r2=m1gm1g+5mg
⇒r1r2<1

So, left arm is shorter than the right arm.

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About this question

This is a previous-year question from JEE Main 2017, covering the Rotational Motion 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.