Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
JEE Main202628 January 2026Morning ShiftPhysicsRotational MotionActual

Two circular discs of radius each 10 cm are joined at their centres by a rod of length 30 cm and mass 600 gm as shown in figure. If the mass of each disc is 600 gm and applied torque between two discs is 43 10⁵ dyne. cm, the angular acceleration of the discs about the given axis A B is _ _ _ _ rad / s ² .

Options

  1. A11
  2. B22
  3. C100
  4. D27

Correct answer

A. 11

Step-by-step solution

= I I = 1 4 mR^2 + mR^2 + 1 4 mR^2 + m(2R)^2 + m(3R)^2 12 + m ( R 2 )^2 = ( 3 2 + 4 + 1 )mR^2 = 13 2 mR^2 = 13 2 600 10^2 = 39 10^4 = 43 10^5 39 10^4 rad/s ^2 = 430 39 rad/s ^2 11 rad/s ^2

Practice Rotational Motion on Quantrex Academy →

More from Rotational Motion

Consider a large disk of radius R and two smaller disks, each of radius r = R/50 , lying on its circumference, as shown in the figure. The smaller disks are initially in contact wi 2026A solid cylinder of radius R rolls without slipping with a center of mass speed v₀ = gR 3 on a horizontal surface with a vertical edge, as shown in the figure. Here, g is the accel 2026List-I shows four planar structures made of uniform solid rods each of mass m and length l . In the List-II the possible moment of inertia of these structures about an axis OCO' , 2026Passage: A uniform circular disk of radius 0.2 m and mass 1 kg is pivoted at its top point C such that it can rotate freely around C in the XY plane, as shown in the figure. Initia 2026Passage: A uniform circular disk of radius 0.2 m and mass 1 kg is pivoted at its top point C such that it can rotate freely around C in the XY plane, as shown in the figure. Initia 2026A solid cylinder having radius R and length L is slipping on a rough horizontal plane. At time t=0 the cylinder has a translational velocity v₀=49 m/s, perpendicular to its axis an 2026A solid sphere ( A ) of mass 5m and a spherical shell ( B ) of mass m , both having same radius, are placed on a rough surface. When a force of same magnitude is applied tangential 2026A solid sphere of radius 4 cm and mass 5 kg is rotating (rotation axis is passing through the centre of the sphere) with an angular velocity of 1200 rpm. It is brought to rest in 1 2026 Full Rotational Motion list All JEE Main PYQs