Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
JEE Advanced 2021Paper 1
Exam
JEE Advanced
Year
2021
Paper
Paper 1
Subject
Physics
Chapter
Rotational Motion

JEE Advanced 2021 · Paper 1 · Physics · Rotational Motion

A horizontal force F is applied at the centre of mass of a...

A horizontal force FF is applied at the centre of mass of a cylindrical object of mass mm and radius RR, perpendicular to its axis as shown in the figure. The coefficient of friction between the object and the ground is μ\mu. The centre of mass of the object has an acceleration aa. The acceleration due to gravity is gg. Given that the object rolls without slipping, which of the following statement(s) is (are) correct?

A horizontal force F is applied at the centre of mass of a cylindrical object of mass m and radius R , perpendicular to

Options

  1. AFor the same FF, the value of aa does not depend on whether the cylinder is solid or hollow.
  2. BFor a solid cylinder, the maximum possible value of aa is 2\mug2\mug.
  3. CThe magnitude of the frictional force on the object due to the ground is always \mumg\mumg.
  4. DFor a thin-walled hollow cylinder, a=F2ma = \dfrac{F}{2m}.

Correct answer

B. For a solid cylinder, the maximum possible value of aa is 2\mug2\mug.

Step-by-step solution

Let moment of inertia =I= I

A horizontal force F is applied at the centre of mass of a cylindrical object of mass m and radius R , perpendicular to

For pure rolling, a=\alphaRa = \alphaR

and F−f=ma...(1)F - f = ma . . . \left(1\right)

and fR=IαfR = I\alpha

or fR=IaRfR = \dfrac{Ia}{R}

or f=IaR2f = \dfrac{Ia}{{R}^{2}}

Therefore, F−IaR2=maF - \dfrac{Ia}{{R}^{2}} = ma

∴F=(m+IR2)a∴ F = \left(m + \dfrac{I}{{R}^{2}}\right)a

⇒⇒ For the same value of FF, value of aa depends on II.

⇒⇒ For a solid cylinder\left(I = \dfrac{m{R}^{2}}{2}\right)(tocalculatemaximum(to calculate maximuma)</p><p>)</p><p>f = \mumg</p><p></p><p>∴ \mumg = \left(\dfrac{m{R}^{2}}{2}\right) \times \dfrac{a}{{R}^{2}}</p><p>Therefore,</p><p>Therefore,a = 2\mug</p><p></p><p>⇒ fisdependentonappliedforce.</p><p>is dependent on applied force.</p><p>⇒Forthin−walledhollowcylinder(I=mR2)For thin-walled hollow cylinder\left(I = m{R}^{2}\right),

F=(m+mR2R2)a=2maF = \left(m + \dfrac{m{R}^{2}}{{R}^{2}}\right)a = 2ma

∴a=F2m∴ a = \dfrac{F}{2m}

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… JEE Advanced 2026A solid cylinder of radius R rolls without slipping with a center of mass speed v_0 =… JEE Advanced 2026List-I shows four planar structures made of uniform solid rods each of mass m and length… JEE Advanced 2026Passage: A uniform circular disk of radius 0.2 m and mass 1 kg is pivoted at its top… JEE Advanced 2026Passage: A uniform circular disk of radius 0.2 m and mass 1 kg is pivoted at its top… JEE Advanced 2026A solid cylinder having radius R and length L is slipping on a rough horizontal plane. At… JEE Main 2026A solid sphere ( A ) of mass 5m and a spherical shell ( B ) of mass m , both having same… JEE Main 2026A solid sphere of radius 4 cm and mass 5 kg is rotating (rotation axis is passing through… JEE Main 2026 Full Rotational Motion list All JEE Advanced PYQs