rotational motion iit jee questions

0


rotational motion iit jee questions


Welcome, To STUDYEVERTHING
Today, we are going to cover the MOST IMPORTANT QUESTION from PHYSICS chapter Rotational motion for exams like CBSE board, NEET, JEE MAIN & JEE ADVANCE.

First try to solve the question on your own in the allotted time (45 minutes). Then check the answers.

If you want to know the answers in detail you can simply download the pdf file which is at the end of the session.

So, what are you waiting for,
Let's crack it.





You may choose the language using translater, located at top of the right-hand side, as Hindi, Gujarati, etc.












STUDY EVERTHING



TIMER:

45min










1. A disc of mass m and radius r rolling with a angular speed Ω on a horizontal plane as shown in figure. The magnitude of angular momentum of the disc about the origin is


a.1/2MR2Ω
b.MR2 Ns
c.3/2MR2Ω
d.2MR2Ω




2. A cylinder and sphere have the same mass and same radius. The moment of inertia of the cylinder about its longitudinal axis is I1 and that of the sphere about its diameter in I1 .  The ratio of I1 / I1 will be
a.2/3
b.3/2
c.1
d.5/4




3. Two point masses of 0.3kg and 0.7kg are fixed at the ends of a rod of length 1.4m and negligible mass. The today is set rotating about an axis perpendicular to its length with a uniform angular speed. The point on the rod through which the axis should pass in order that the work required for the rotation of the rod is minimum, is located at a distance of
a.0.42m from mass of 0.3kg
b.0.73m from mass of 0.7kg
c.0.98m from mass of 0.3kg
d.0.98 from mass of 0.7kg





4. A string of negligible thickness would several times around a cylinder (of circumference l) is kept on a rough horizontal surface. A man standing at a distance l from the cylinder holds one end of the string and pulls the cylinder towards him (see figure). There is no slipping anywhere. The length of the string passing through the hand of the man while the cylinder reaches his hand is.

a.l
b.2l
c.3l
d.4l



5. A smooth sphere A is moving on a frictionless horizontal plane with angular speed Ω and centre of mass velocity v it collide elastically and head on with an identical sphere B at rest. Neglect friction everywhere. After the collision their angular speeds are Ωa and Ωb respectively. Then,
a. Ωa > Ωb
b. Ωa = Ωb
c. Ωa = Ω
d. Ωb = Ω





6. A long horizontal rod has a bead which can slide along its length and initially placed at a distance L from one end of the rod. The today is set in angular motion about A with constant angular acceleration α. If the coefficient of friction between rod and the bead is μ and gravity is neglected then the time after which the bead start slipping is

a.(μ/α)1/2
b.μ/α1/2
c.1/(μα)1/2
d.infinitesimal





7. A thin wire of length l and uniform linear mass density ρ is bent into a circular loop with centre O as shown in figure. The moment of inertia of the loop about the axis XX' is

a. ρL3/8π2
b.ρL3/16π2
c.5ρL3/16π2
d.3ρL3/8π2





8. One quarter circle is cut from a uniform circulation disc of radius R. This sector if mass M. It is made to rotate along a line perpendicular to its plane and passing through the centre of the original disc. Its moment of inertia about the axis of rotation is


a.1/2MR2
b.1/4MR2
c.1/8MR2
d.√2MR2





9. Consider a body, as shown in figure, consisting two identical balls, each of mass M connected by a light rigid rod. If the impluse J=MV is imparted to the body at one of its end , what would be its angular velocity

a.V/L
b.2V/L
c.V/3L
d.V/4L







10. A horizontal vertical plate is rotating about a vertical axis passing through its centre with angular speed Ω. A man sitting at the centre having two blocks in his hands stretchs out his hands so the moment of inertia of the system doubles. If the kinetic energy of the system K initially, its final kinetic energy will be
a.2K
b.K/2
c.K
d.K/4






NUMERICAL TYPE


1. The height above the ground of a child on a swing varies from 1m at his lowest point to 2.25m at his highest point. The maximum speed (in m/s) of the child is approximately





2. Two particle A and B initially at rest, move toward each other under mutual force of attraction. At the instant the speed of A is V and speed of B is 2V,the speed of the centre of mass of the system





3. The minimum velocity(in m/s) with the car driver must transverse a flat car if radius 150m and coefficient of friction 0.6 to avoid skidding is





4. A cylinder of height 20m is completely filled with water(in m/s) the velocity of efflux of the water through a small hole on the side wall of the cylinder near its bottom is





5. A circular disc of radius R is removed from a bigger circular disc of radius 2R such that the circumference of the disc coincide. The centre of the mass of the new disc is α/4 from the centre of mass of the bigger disc. The value of α is




JEE ADVANCE


1. A rectangular plate of mass M and dimension a×b is held on a horizontal position by striking n small balls (each of mass m) per unit area per second. The balls are striking in the shaded half region of the plate. The collision of the ball with plate is elastic. Find v?
Given n=100, M=3kg, m=0.03kg, b=2m, a=1m, g=10m/s2

a.10
b.100
c.60
d.20





2. A uniform disc of mass 50kg and radius 0.4m is rotating with angular velocity of 10 rad/s of its own axis, which is vertical, two uniform circular ring each of mass 6.25kg and radius 0.2m are gently placed symmetrically on the disc in such a manner that they are touching each other along the axis of the disc and horizontal. Assume that friction is large enough such that the rings are at rest relative to the disc and the system rotates about the original axis. The new angular velocity(in rad/s) of the disc is
a.6
b.8
c.10
d.2





3. The densities of two spheres A and B of same radii R varies with the radial distance r as ρA(r)=k(r/R) and ρB(r)=k(r/R)5, respectively, where I is a constant. The moment of inertia of the individual sphere about the axis passing through their centre are I1 and I2, respectively. If I1/I2= n/10. The value of n is
a.3
b.2
c.6
d.9





4. Let I be the inertia of uniform square plate about a axis AB that passes through its centre and is parallel to two of its side. CD is a line that passes through the centre of the plate and makes angle θ with AB. The moment of inertia of the plate about the axis CD is then equal to
a.I
b.Isin2θ
c. Icos2θ
d. Isin2(θ/2)




5. Two identical disc roll without slipping on two different surface AB and CD(see figure) starting at A and C with linear speeds v1 and v2, respectively, and always remains contact with surface. If they reach B and D with same linear speed and v1= 3m/s and then v2 in m/s is (g=10 m/s2)


a.6
b.5
c.7
d.9




Download the detailed answer pdf of the most important questions from Chapter
Rotational motion.


Unit and measurements  most important  questions click here
Kinamatic most important questions click here
Law of motion most important questions click here
Work, energy and power most important questions click here
Nit cutoff click here
Iiit cutoffclick here




Please, write your score in the comment box.

Thankyou.

You may like these posts

Post a Comment

If you have furthur QUERIES please let us know

Previous Post Next Post