Practice free Rotational Motion (Physics) NEET multiple-choice questions online with instant answers and detailed explanations. No login required.
A solid cylinder rolls down a smooth inclined plane 4.8m high without slipping what
is its linear speed at the bottom of the plane, if it starts rolling from the top of
the plane? $ (take g = 10 m/S^2) $
$ V = \sqrt { 2gh \over 1 + { k^2 \over r^2 } } $
The moment of inertia of a uniform rod about a perpendicular axis passing through one of its ends is I1. The same rod is bent in to a ring and its moment of inertia about a diameter is $I_2 $ . Then $ { I_1 \over I_2 } $ is
For a rod of mass M and length L., the MI about a perpendicular axis passing through one and is $ I _1 = { ML^2 \over 3 } $ when it is bent to form a ring, then $ L = 2 \pi R $ $ \therefore R = { L \over 2} \pi $ The M.I of the ring about its diameter is $ I_2 = { MR^2 \over 2} = { ML^2 \over 4 \pi^2 .2 } = { ML^2 \over 8 \pi^2 } $
A molecule consist of two atoms each of mass 'm' and separated by a distance
of 'd' If 'K' is the average rotational K.E. of the molecule at particular temperature
then its angular frequency is….
The M.I of the molecule = $ M \left( { d \over 2 } \right) + m \left( { d \over 2} \right)^2 $ $ I = 2m \left( { d^2 \over 4 } \right) = { md^2 \over 2 } $ The Rotational K.E. of the moldule $ (K) = { 1 \over 2} I \omega^2 $ $ \omega = \sqrt { 2K \over I } $
A car is moving with a constant speed the wheels of the car make 120 rotations per minute the breaks are applied and the car comes to rest in 8 sec how many rotation are completed by the wheels before the car is brought to rest.
$ \omega_0 = { 2 \pi \times 120 \over 60} = 4 \pi rad /sec $ Now $ \omega = \omega_0 + \alpha t $ Total angle descrited in 8 second is $ \theta = w_0 t + { 1 \over 2} \alpha t^2 $
The angular momentum of a wheel changes from 2L to 5L in 3 seconds what is the magnitudes of torque acting on it?
$ \tau = { dL \over dt} = { 5L - 2L \over 3 } ={ 3L \over 3 } + L $
A uniform disc of mass 500kg and radius 2 m is rotating at the rate of 600 r.p.m. what is the torque required to rotate the disc in the opposite direction with the same angular speed in a time of 100 sec ?
$ For disc I = { MR^2 \over 2} = { 500 \times 4 \over 2 } $ $ angular speed = \omega = { 2 pi \times 600 \over 60 } $ so angular momentum $ L = I \omega$ final angular momentum in opposite direction $ = -1000 \times 20 \pi kgm^2 / sec $ So change in angular momentum = $ \triangle = 2 \times 1000 \times 20 \pi kg m^2 / sec $ $ \tau = { dL \over dt } = { 2 times 1000 \times 20 \pi \over 100 } = 400 \pi N.m$
The moment of inertia of a meter scale of mass 0.6kg about an axis perpendicular to the scale and passing through 30 cm position on the scale is given by (Breath of scale is negligible).
By Parallel axis therom solved problem
How much constant force should be applied tangential to equator of the earth to stop its rotation in one day ?
$ \omega_1 = 2 \pi rad/day and \omega_2 = 0 , t =1 day $ $ \alpha = { w_2 - w_1 \over t } $ Torque required to stop the earth = T = $ I \alpha $ = F.R $ F = { I.\alpha \over R } $
A constant torque of 1500 Nm turns a wheel of moment of inertia 300 kg m2 about an axis passing through its centre the angular velocity of the wheel after 3 sec will be….. rad/sec
$ \tau = I \alpha = I { d \omega \over dt} $
A mass m is moving with a constant velocity along the line parallel to the x-axis, away from the origin. Its angular momentum with respect to the origin
$ L = Momentum \times perpenlicular distance between point of rotation and line of action $ = m.V.y all remain constant L = remaing constant
Ready to ace NEET?
Free access · No credit card required
Yes. You can attempt every Rotational Motion question on this page for free without logging in, and check the correct answer with a detailed explanation instantly.
No account is required to attempt questions and view answers. A free account adds bookmarks, personal notes, and progress tracking.
The bank mixes NEET previous year questions (PYQs) with practice questions, each tagged with its exam appearances where applicable.