Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
JEE MainPhysicsRotational Motion

A uniform solid cylinder of mass 2 kg and radius 10 cm is rotated about its central geometric axis with an angular speed of 5 rad s ⁻¹ . If the moment of inertia of the cylinder about a generator (a line on the surface parallel to the central axis) is numerically equal to x 10⁻¹ times its angular momentum about the central axis, then the value of x is

Correct answer

6

Step-by-step solution

The moment of inertia of a solid cylinder about its central axis is I_ central = 1 2 MR^2 The angular momentum about the central axis is L = I_ central = ( 1 2 MR^2 ) 5 = 5 2 MR^2 Using the parallel axis theorem, the moment of inertia about a generator (a line on the surface parallel to the central axis at a distance R ) is I_ gen = I_ central + MR^2 = 1 2 MR^2 + MR^2 = 3 2 MR^2 According to the given condition, I_ gen = x 10⁻¹ L 3 2 MR^2 = x 10 5 2 MR^2 3 = x 10 5 x = 6 Answer: 6

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