The JEE Main Physics section requires speed and accuracy, along with a thorough understanding of the System of Particles & Rotational Motion. This article provides a set of JEE Main PYQs on System of Particles & Rotational Motion to help you understand the topic and improve your problem-solving skills with the help of detailed solutions by ensuring conceptual clarity, which will help you in the JEE Main 2026 preparation.
Whether you're revising the basics or testing your knowledge, these JEE Main PYQs will serve as a valuable practice resource.
The JEE Main 2026 exam is likely to continue on the same pattern as JEE Main 2025. Out of 90 questions, students can expect a fair mix from all three subjects. To get an edge, going through JEE Main previous year questions (PYQs) is one of the best strategies.
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JEE Main PYQs on System of Particles & Rotational Motion
1.
The temperature of a body in air falls from \( 40^\circ \text{C} \) to \( 24^\circ \text{C} \) in 4 minutes. The temperature of the air is \( 16^\circ \text{C} \). The temperature of the body in the next 4 minutes will be:- 28/3 °C
- 14/3 °C
56/3 °C
42/3 °C
2.
A circular disc $D_1$ of mass $M$ and radius $R$ has two identical discs $D_2$ and $D_3$ of the same mass $M$ and radius $R$ attached rigidly at its opposite ends (see figure). The moment of inertia of the system about the axis $OO'$, passing through the centre of $D_1$, as shown in the figure, will be :- $3 MR^2$
- $\frac{2}{3} MR^2$
- $MR^2$
- $\frac{4}{5} MR^2$
3.
A rod of length $L$ has non-uniform linear mass density given by $\rho\left(x\right)=a+b\left(\frac{x}{L}\right)^{2},$ where a and b are constants and $0 \le x \le L.$ The value of $x$ for the centre of mass of the rod is a t :- $\frac{3}{2}\left(\frac{2a+b}{3a+b}\right)L$
- $\frac{3}{2}\left(\frac{a+b}{2a+b}\right)L$
- $\frac{3}{4}\left(\frac{2a+b}{3a+b}\right)L$
- $\frac{4}{3}\left(\frac{a+b}{2a+3b}\right)L$
4.
Two uniform circular discs are rotating independently in the same direction around their common axis passing through their centres. The moment of inertia and angular velocity of the first disc are $0.1\, kg - m ^{2}$ and $10 \,rad\, s^{-1}$ respectively while those for the second one are $0.2\, kg - m ^{2}$ and $5\, rad \,s ^{-1}$ respectively. At some instant they get stuck together and start rotating as a single system about their common axis with some angular speed. The Kinetic energy of the combined system is :- $\frac{10}{3}\, J$
- $\frac{2}{3}\, J$
- $\frac{5}{3}\, J$
- $\frac{20}{3} \,J$
5.
A rigid massless rod of length $3l$ has two masses attached at each end as shown in the figure. The rod is pivoted at point $P$ on the horizontal axis (see figure). When released from initial horizontal position, its instantaneous angular acceleration will be :- $\frac{g}{2l}$
- $\frac{7g}{3l}$
- $\frac{g}{13l}$
- $\frac{g}{3l}$
6.
A rectangular solid box of length $0.3\, m$ is held horizontally, with one of its sides on the edge of a platform of height $5\,m$. When released, it slips off the table in a very short time $\tau = 0.01\,s$, remaining essentially horizontal. The angle by which it would rotate when it hits the ground will be (in radians) close to :- 0.02
- 0.28
- 0.5
- 0.3
7.
A particle is moving in circular path of radius r speed v such that speed is proportional to radius as \(V∝ r^{\frac{3}{2}}\). Then how does time period of revolution depends on r i.e Trn then \(n\) is.- \(-\frac{1}{2}\)
- \(\frac{5}{2}\)
- \(-\frac{5}{2}\)
- \(\frac{1}{2}\)
8.
A string is wound around a hollow cylinder of mass $5\, kg$ and radius $0.5\, m$. If the string is now pulled with a horizontal force of $40\, N$, and the cylinder is rolling without slipping on a horizontal surface (see figure), then the angular acceleration of the cylinder will be (Neglect the mass and thickness of the string) :- $12 \; rad/s^2$
- $16 \; rad/s^2$
- $10 \; rad/s^2$
- $20 \; rad/s^2$
9.
The temperature of a body in air falls from \( 40^\circ \text{C} \) to \( 24^\circ \text{C} \) in 4 minutes. The temperature of the air is \( 16^\circ \text{C} \). The temperature of the body in the next 4 minutes will be:- \( \frac{28}{3} \, ^\circ \text{C} \)
- \( \frac{14}{3} \, ^\circ \text{C} \)
- \( \frac{56}{3} \, ^\circ \text{C} \)
- \( \frac{42}{3} \, ^\circ \text{C} \)
10.
A solid cylinder of radius R and length L have moment of inertia I1 and a second solid cylinder of radius R2 and length L2 cut from it have moment of inertia I2. Find 11/I2.
64
32
128
256
11.
The center of mass of a thin rectangular plate (fig - x) with sides of length \( a \) and \( b \), whose mass per unit area (\( \sigma \)) varies as \( \sigma = \sigma_0 \frac{x}{ab} \) (where \( \sigma_0 \) is a constant), would be
- \( \left(\frac{2}{3} a, \frac{2}{3} b\right) \)
- \( \left(\frac{1}{3} a, \frac{1}{2} b\right) \)
- \( \left(\frac{1}{2} a, \frac{1}{2} b\right) \)
- \( \left(\frac{2}{3} a, \frac{1}{2} b\right) \)
12.
A bead of mass \(m\) stays at point \(P(a, b)\) on a wire bent in the shape of a parabola \(y=4 c x^{2}\) and rotating with angular speed \(\omega\) (see figure).
The value of \(\omega\) is (neglect friction) :- $\sqrt{\frac{2 gC }{ ab }}$
- $2 \sqrt{2 gC }$
- $\sqrt{\frac{2 g }{ C }}$
- $2 \sqrt{ gC }$
13.
The center of mass of a thin rectangular plate (fig - x) with sides of length \( a \) and \( b \), whose mass per unit area (\( \sigma \)) varies as \( \sigma = \sigma_0 \frac{x}{ab} \) (where \( \sigma_0 \) is a constant), would be
\( \left(\frac{2}{3} a, \frac{b}{2} \right) \)
- \( \left(\frac{1}{3} a, \frac{1}{2} b\right) \)
- \( \left(\frac{1}{2} a, \frac{1}{2} b\right) \)
- \( \left(\frac{2}{3} a, \frac{1}{2} b\right) \)
14.
Match List - I with List - II: List - I:- (A) Electric field inside (distance \( r > 0 \) from center) of a uniformly charged spherical shell with surface charge density \( \sigma \), and radius \( R \).
- (B) Electric field at distance \( r > 0 \) from a uniformly charged infinite plane sheet with surface charge density \( \sigma \).
- (C) Electric field outside (distance \( r > 0 \) from center) of a uniformly charged spherical shell with surface charge density \( \sigma \), and radius \( R \).
- (D) Electric field between two oppositely charged infinite plane parallel sheets with uniform surface charge density \( \sigma \).
- (I) \( \frac{\sigma}{\epsilon_0} \)
- (II) \( \frac{\sigma}{2\epsilon_0} \)
- (III) 0
- (IV) \( \frac{\sigma}{\epsilon_0 r^2} \)
- \( {(A)-(IV)}, {(B)-(II)}, {(C)-(III)}, {(D)-(I)} \)
- \( {(A)-(IV)}, {(B)-(I)}, {(C)-(III)}, {(D)-(II)} \)
- \( {(A)-(III)}, {(B)-(II)}, {(C)-(IV)}, {(D)-(I)} \)
- \( {(A)-(I)}, {(B)-(II)}, {(C)-(IV)}, {(D)-(III)} \)
15.
A particle of mass $m$ is fixed to one end of a light spring having force constant $k$ and unstretched length $l$. The other end is fixed. The system is given an angular speed $\omega$ about the fixed end of the spring such that it rotates in a circle in gravity free space. Then the stretch in the spring is :- $\frac{ml\omega^{2}}{k - \omega m}$
- $\frac{ml\omega^{2}}{k - m\omega^{2}}$
- $\frac{ml\omega^{2}}{k + m\omega^{2}}$
- $\frac{ml\omega^{2}}{k + m\omega}$
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