Skip to main content

A small bob A of mass m is attached to a massless rigid rod of length 1 m pivoted at point P and kept at an angle of 60° with vertical as shown in…

JEE Main 2026 — Physics Mechanics

2026mcqhard

A small bob AAA of mass mmm is attached to a massless rigid rod of length 1 m pivoted at point PPP and kept at an angle of 60∘60^{\circ}60∘ with vertical as shown in figure. At distance of 1 m below point PPP, an identical bob BBB is kept at rest on a smooth horizontal surface that extends to a circular track of radius RRR as shown in figure. If bob BBB just manages to complete the circular path of radius RRR upto a point QQQ after being hit elastically by bob⁡A\operatorname{bob} AbobA, then radius RRR is ____\_\_\_\_____ m.

JEE Main 2026 Physics, Work Power Energy — question figure

Official previous-year question

Held on 23 Jan 2026 · Verified 6 Jul 2026.

Options

  1. A

    15\frac{1}{5}51​

  2. B

    2−35\frac{2-\sqrt{3}}{5}52−3​​

  3. C

    35\frac{3}{5}53​

  4. D

    2+35\frac{2+\sqrt{3}}{5}52+3​​

Did you get this right?

Sign in to track your attempts and accuracy.

Your note

Sign in to keep a private note on this question. Nothing you write is ever public.

JEE Main Mechanics in other years

More JEE Main Mechanics questions

If $\epsilon, E$ and $t$ represent the free space permittivity, electric field and time respectively, then the unit of $\frac{\epsilon E}{t}$ will be :

2026easy

When a part of a straight capillary tube is placed vertically in a liquid, the liquid raises upto certain height $h$. If the inner radius of the capillary tube, density of the liquid and surface tension of the liquid decrease by $1 \%$ each, then the height of the liquid in the tube will change by $\%$.

2026medium

The velocity of a particle is given as $\vec{v} = -x\hat{i} + 2y\hat{j} - z\hat{k}$ m/s. The magnitude of acceleration at point $(1, 2, 4)$ is _______ m/s$^2$.

2026hard

Suppose there is a uniform circular disc of mass $M \mathrm{~kg}$ and radius $r \mathrm{~m}$ shown in figure. The shaded regions are cut out from the disc. The moment of inertia of the remainder about the axis $A$ of the disc is given by $\frac{x}{256} M r^{2}$. The value of $x$ is $\_\_\_\_$. ![JEE Main 2026 Physics, Rotational Motion — question figure](https://prepforbharat.s3.ap-south-1.amazonaws.com/exam/615f0e999476412f48314daf/Physics/images/Rotational_Motion/6983c19b8bfdbb24356396d6/question_1__q_6983c19b8bfdbb24356396d6__cdn-question-pool.getmarks.app__23S2_q_48_1__7376098484_final_ppt_sync.png)

2026hard

A soap bubble of surface tension $0.04 \mathrm{~N} / \mathrm{m}$ is blown to a diameter of 7 cm. If $(15000-x) \mu \mathrm{J}$ of work is done in blowing it further to make its diameter 14 cm, then the value of $x$ is $\_\_\_\_$. ($\pi=22 / 7$)

2026medium

Other Physics topics for JEE Main

Keep practicing Mechanics

Work through every JEE Main Mechanics PYQ, year by year.

Browse all Physics topics