PYQSidePowered byPrepblink ExamsMy practice

System of Particles and Rotational Motion

JEE Main 2025 (Online) 22nd January Morning ShiftMCQMedium📈 Topic in 21% papers+4−1
Ques. 1JEE Main 2025, 22 January (Morning Shift)

A uniform circular disc of radius ' R ' and mass ' M ' is rotating about an axis perpendicular to its plane and passing through its centre. A small circular part of radius R/2 is removed from the original disc as shown in the figure. Find the moment of inertia of the remaining part of the original disc about the axis as given above. [figure]

  1. 1732MR2
  2. 1332MR2
  3. 932MR2
  4. 732MR2

Answer

(2) 1332MR2

Solution

Remaining disc = full disc - removed disc (same axis through O).

[figure]

m= M4 (area), Ifull= 12MR2

Removed disc (parallel axis, distance R2):

I= 12m ( R2 )2+m ( R2 )2

= 38mR2= 332MR2

I= 12MR2- 332MR2= 1332MR2

Answer: (2)

Keep practising — System of Particles and Rotational Motion

Ques. 2JEE Main 2025, 22 January (Morning Shift)

The position vectors of two 1 kg particles, (A) and (B), are given by rA= ( 1t2 i+ 2t j+ 3t k )m and rB= ( 1t i+ 2t2 j+ 3t k )m, respectively; ( 1=1 m/s2, 2=3n m/s, 3=2 m/s, 1=2 m/s, 2=-1 m/s2, 3=4p m/s), where t is time, n and p are constants. At t=1 s, | VA |= | VB | and velocities VA and VB of the particles are orthogonal to each other. At t=1 s, the magnitude of angular momentum of particle (A) with respect to the position of particle (B) is L kg m2 s-1. The value of L is .

Ques. 3JEE Main 2025, 22 January (Evening Shift)

The torque due to the force (2 i+ j+2 k ) about the origin, acting on a particle whose position vector is ( i+ j+ k ), would be

  1. j+ k
  2. i- k
  3. i- j+ k
  4. i+ k

All System of Particles and Rotational Motion PYQs →

PDFDownload System of Particles and Rotational Motion PYQs as PDF Free, with answer key and a QR code to every solution — print it or study offline⬇
All JEE Main Physics chapters
Class 11Units and MeasurementsMotion in a Straight LineMotion in a PlaneLaws of MotionWork, Energy and PowerSystem of Particles and Rotational MotionGravitationMechanical Properties of SolidsMechanical Properties of FluidsThermal Properties of MatterThermodynamics (Physics)Kinetic TheoryOscillationsWaves
Class 12Electric Charges and FieldsElectrostatic Potential and CapacitanceCurrent ElectricityMoving Charges and MagnetismMagnetism and MatterElectromagnetic InductionAlternating CurrentElectromagnetic WavesRay Optics and Optical InstrumentsWave OpticsDual Nature of Radiation and MatterAtomsNucleiSemiconductor ElectronicsExperimental Skills (Physics)